Saturday 2 September 2023

 Have you ever wondered what’s happening inside 

your computer when you load a program or video  

game? Well, millions of operations are happening, 

but perhaps the most common is simply just copying  

data from a solid-state drive or SSD into dynamic 

random-access memory or DRAM.  An SSD stores all  

the programs and data for long-term storage, 

but when your computer wants to use that data,  

it has to first move the appropriate 

files into DRAM, which takes time,  

hence the loading bar. Because your CPU works 

only with data after it’s been moved to DRAM,  

it’s also called working memory or main memory.

The reason why your desktop uses both SSDs and  

DRAM is because Solid-State Drives permanently 

store data in massive 3D arrays composed of a  

trillion or so memory cells, yielding terabytes of 

storage, whereas DRAM temporarily stores data in  

2D arrays composed of billions of tiny capacitor 

memory cells yielding gigabytes of working memory.  

Accessing any section of cells in the massive 

SSD array and reading or writing data takes  

about 50 microseconds whereas reading or 

writing from any DRAM capacitor memory  

cell takes about 17 nanoseconds, which is 3000 

times faster. For comparison, a supersonic jet  

going at Mach 3 is around 3000 times faster 

than a moving tortoise. So, the speed of  

17 nanosecond DRAM versus 50 microsecond SSD is 

like comparing a supersonic jet to a tortoise.  

  However, speed is just one factor. DRAM is 

limited to a 2D array and temporarily stores  

one bit per memory cell. For example, this stick 

of DRAM with 8 chips holds 16 gigabytes of data,  

whereas a solid-state drive of a smaller 

size can hold 2 terabytes of data, more  

than 100 times that of DRAM. Additionally, 

DRAM requires power to continuously store  

and refresh the data held in its capacitors.  

Therefore, computers use both SSDs and DRAM and,  

by spending a few seconds of loading time 

to copy data from the SSD to the DRAM,  

and then prefetching, which is the process of 

moving data before it’s needed, your computer can  

store terabytes of data on the SSD and then access 

the data from programs that were preemptively  

copied into the DRAM in a few nanoseconds. 

For example, many video games have a loading  

time to start up the game itself, and then a 

separate loading time to load a save file.   

During the process of loading a save file, all 

the 3D models, textures, and the environment of  

your game state are moved from the SSD into DRAM 

so any of it can be accessed in a few nanoseconds,  

which is why video games have DRAM capacity 

requirements. Just imagine, without DRAM,  

playing a game would be 3,000 times slower.  

We covered solid-state drives in other videos,  

so in this video, we’re going to take a deep 

dive into this 16-gigabyte stick of DRAM. First,  

we’ll see exactly how the CPU communicates 

and moves data from an SSD to DRAM. Then  

we’ll open up a DRAM microchip and see how 

billions of memory cells are organized into  

banks and how data is written to and read from 

groups of memory cells. In the process, we’ll  

dive into the nanoscopic structures inside 

individual memory cells and see how each  

capacitor physically stores 1 bit of data.  

Finally, we’ll explore some breakthroughs and  

optimizations such as the burst buffer and folded 

DRAM layouts that enable DRAM to move data around  

at incredible speeds. A few quick notes.  

First, you can find similar DRAM chips inside  

GPUs, Smartphones, and many other devices, but 

with different optimizations. As examples,  

GPU DRAM or VRAM, located all around the 

GPU chip, has a larger bandwidth and can  

read and write simultaneously, but operates at 

a lower frequency, and DRAM in your smartphone  

is stacked on top of the CPU and is optimized for 

smaller packaging and lower power consumption.   

Second, this video is sponsored by 

Crucial. Although they gave me this  

stick of DRAM to model and use in the 

video, the content was independently  

researched and not influenced by them.  

Third, there are faster memory structures  

in your CPU called cache memory and even faster 

registers. All these types of memory create a  

memory hierarchy, with the main trade-off 

being speed versus capacity while keeping  

prices affordable to consumers and optimizing 

the size of each microchip for manufacturing. 

Fourth, you can see how much of 

your DRAM is being utilized by  

each program by opening your computer’s 

resource monitor and clicking on memory. 

Fifth, there are different generations of DRAM, 

and we’ll explore DDR5. Many of the key concepts  

that we explain apply to prior generations, 

although the numbers may be different.   

Sixth, 17 nanoseconds is incredibly fast!  

Electricity travels at around 1 foot per  

nanosecond, and 17 nanoseconds is about the 

time it takes for light to travel across a room. 

Finally, this video is rather long as it covers 

a lot of what there is to know around DRAM. We  

recommend watching it first at one point two 

five times speed, and then a second time at  

one and a half speed to fully comprehend this 

complex technology. Stick around because this  

is going to be an incredibly detailed video.  

To start, a stick of DRAM is also called a Dual  

Inline Memory Module or DIMM and there are 8 

DRAM chips on this particular DIMM. On the  

motherboard, there are 4 DRAM slots, and when 

plugged in, the DRAM is directly connected to  

the CPU via 2 memory channels that run through 

the motherboard. Note that the left two DRAM  

slots share these memory channels, and the right 

two share a separate channel. Let’s move to  

look inside the CPU at the processor. Along 

with numerous cores and many other elements,  

we find the memory controller which manages 

and communicates with the DRAM. There’s also  

a separate section for communicating with SSDs 

plugged into the M2 slots and with SSDs and  

hard drives plugged into SATA connectors. Using 

these sections, along with data mapping tables,  

the CPU manages the flow of data from 

the SSD to DRAM, as well as from DRAM  

to cache memory for processing by the cores.

Let’s move back to see the memory channels.   

For DDR5 each memory channel is divided into two 

parts, Channel A and Channel B. These two memory  

channels A and B independently transfer 32 bits at 

a time using 32 data wires.  Using 21 additional  

wires each memory channel carries an address 

specifying where to read or write data and, using  

7 control signal wires, commands are relayed.

The addresses and commands are sent to and shared  

by all 4 chips on the memory channel which 

work in parallel. However, the 32-bit data  

lines are divided among the chips and thus each 

chip only reads or writes 8 bits at a time.   

Additionally, power for DRAM is 

supplied by the motherboard and  

managed by these chips on the stick itself.

Next, let’s open and look inside one of these  

DRAM microchips. Inside the exterior packaging, 

we find an interconnection matrix that connects  

the ball grid array at the bottom with the die 

which is the main part of this microchip. This 2  

gigabyte DRAM die is organized into 8 bank groups 

composed of 4 banks each, totaling 32 banks.   

Within each bank is a massive array, 65,536 memory 

cells tall by 8192 cells across, essentially rows  

and columns in a grid, with tens of thousands of 

wires, and supporting circuitry running outside  

each bank. Instead of looking at this die, we’re 

going to transition to a functional diagram,  

and then reorganize the banks and bank groups.

In order to access 17 billion memory cells,  

we need a 31-bit address. 3 bits are used to 

select the appropriate bank group, then 2 bits  

to select the bank. Next 16 bits of the address 

are used to determine the exact row out of 65  

thousand. Because this chip reads or writes 8 

bits at a time, the 8192 columns are grouped by  

8 memory cells, all read or written at a time, 

or ‘by 8’, and thus only 10 bits are needed for  

the column address. One optimization is that 

this 31-bit address is separated into two parts  

and sent using only 21 wires. First, the bank 

group, bank, and row address are sent, and then  

after that the column address. Next, we’ll look 

inside these physical memory cells, but first,  

let’s briefly talk about how these structures are 

manufactured as well as this video’s sponsor.    

This incredibly complicated die, 

also called an integrated circuit,  

is manufactured on 300-millimeter silicon wafers, 

2500ish dies at a time. On each die are billions  

of nanoscopic memory cells that are fabricated 

using dozens of tools and hundreds of steps in  

a semiconductor fabrication plant or fab. This 

one was made by Micron which manufactures around  

a quarter of the world’s DRAM, including both 

Nvidia’s and AMD’s VRAM in their GPUs Micron also  

has its own product line of DRAM and SSDs under 

the brand Crucial which, as mentioned earlier,  

is the sponsor of this video. In addition 

to DRAM, Micron is one of the world’s leading  

suppliers of solid-state drives such as this 

Crucial P5+ M2 NVME SSD.  By installing your  

operating system and video games on a Crucial 

NVMe solid-state drive, you’ll be sure to have  

incredibly fast loading times and smooth gameplay, 

and if you do video editing, make sure all those  

files are on a fast SSD like this one as well.  

This is because the main speed bottleneck for  

loading is predominantly limited by the speed of 

the SSD or hard drive where the files are stored. 

For example, this hard drive can only transfer 

data at around 150 megabytes a second whereas  

this Crucial NVMe SSD can transfer data at a 

rate of up to 6,600 megabytes a second, which,  

for comparison is the speed of a moving tortoise 

versus a galloping horse. By using a Crucial NVMe  

SSD, loading a video game that requires gigabytes 

of DRAM is reduced from a minute or more down to  

a couple seconds. Check out the Crucial NVMe 

SSDs using the link in the description below. 

Let’s get back to the details of how DRAM works 

and zoom in to explore a single memory cell  

situated in a massive array. This memory cell is 

called a 1T1C cell and is a few dozen nanometers  

in size. It has two parts, a capacitor to store 

one bit of data in the form of electrical charges  

or electrons and a transistor to access and read 

or write data. The capacitor is shaped like a  

deep trench dug into silicon and is composed of 

two conductive surfaces separated by a dielectric  

insulator or barrier just a few atoms thick, which 

stops the flow of electrons but allows electric  

fields to pass through. If this capacitor 

is charged up with electrons to 1 volt,  

it’s a binary 1, and if no charges are present 

and it’s at 0 volts, it’s a binary 0, and thus  

this cell only holds one bit of data. Designs 

of capacitors are constantly evolving but in  

this trench capacitor, the depth of the silicon is 

utilized to allow for larger capacitive storage,  

while taking up as little area as possible.

Next let’s look at the access transistor and  

add in two wires. The wordline wire connects to 

the gate of the transistor while the bitline wire  

connects to the other side of the transistor’s 

channel. Applying a voltage to the wordline  

turns on the transistor, and, while it’s on, 

electrons can flow through the channel thus  

connecting the capacitor to the bitline. This 

allows us to access and charge up the capacitor  

to write a 1 or discharge the capacitor to write 

a 0. Additionally, we can read the stored value  

in the capacitor by measuring the amount of 

charge. However, when the wordline is off,  

the transistor is turned off, and the capacitor 

is isolated from the bitline thus saving the  

data or charge that was previously written. Note 

that because this transistor is incredibly small,  

only a few dozen nanometers wide, electrons slowly 

leak across the channel, and thus over time the  

capacitor needs to be refreshed to recharge 

the leaked electrons. We’ll cover exactly how  

refreshing memory cells works a little later.

As mentioned earlier, this 1T1C memory cell is  

one of 17 billion inside this single die and is 

organized into massive arrays called banks. So,  

let’s build a small array for illustrative 

purposes. In our array, each of the wordlines  

is connected in rows, and then the bitlines are 

connected in columns. Wordlines and bitlines  

are on different vertical layers so one can 

cross over the other, and they never touch.  

Let’s simplify the visual and use symbols for the 

capacitors and the transistors. Just as before,  

the wordlines connect to each transistor’s control 

gate in rows, and then all the bitlines in columns  

connect to the channel opposite each capacitor. 

As a result, when a wordline is active,  

all the capacitors in only that row are 

connected to their corresponding bitlines,  

thereby activating all the memory cells in that 

row. At any given time only one wordline is  

active because, if more than one wordline were 

active, then multiple capacitors in a column  

would be connected to the bitline and the data 

storage functionalities of these capacitors would  

interfere with one another, making them useless.  

As mentioned earlier, within a single bank there  

are 65,536 rows and 8,192 columns and the 31-bit 

address is used to activate a group of just 8  

memory cells. The first 5 bits select the bank, 

and the next 16-bits are sent to a row decoder  

to activate a single row. For example, this 

binary number turns on the wordline row 27,524,  

thus turning on all transistors in that row and 

connecting the 8,192 capacitors to their bitlines,  

while at the same time the other 65 

thousandish wordlines are all off.   

Here’s the logic diagram for a simple decoder.

The remaining 10 bits of the address are sent  

to the column multiplexer. This multiplexer 

takes in the 8192 bitlines on the top, and,  

depending on the 10-bit address, connects a 

specific group of 8 bitlines to the 8 input  

and output IO wires at the bottom. For example, 

if the 10-bit address we this, then only the  

bitlines 4,784 through 4,791 would be connected 

to the IO wires, and the rest of the 8000ish  

bitlines would be connected to nothing. Here’s 

the logic diagram for a simple multiplexer.   

We now have the means of accessing any 

memory cell in this massive array; however,  

to understand the three basic operations, 

reading, writing, and refreshing let’s add  

two elements to our layout: A sense amplifier 

at the bottom of each bitline, and a read and  

write driver outside of the column multiplexer.

Let’s look at reading from a group of memory  

cells. First the read command and 31-bit address 

are sent from the CPU to the DRAM. The first 5  

bits select a specific bank. The next step is 

to turn off all the wordlines in that bank,  

thereby isolating all the capacitors, and then 

precharge all 8000ish bitlines to .5 volts. Next  

the 16-bit row address turns on a row, and all 

the capacitors in that row are connected to their  

bitlines. If an individual capacitor holds a 1 

and is charged to 1 volt, then some charge flows  

from the capacitor onto the .5-volt bitline, and 

the voltage on the bitline increases. The sense  

amplifier then detects this slight change 

or perturbation of voltage on the bitline,  

amplifies the change, and pushes the voltage on 

the bitline all the way up to 1 volt. However,  

if a 0 is stored in the capacitor, charge 

flows from the bitline into the capacitor,  

and the .5-volt bitline decreases in voltage.  

The sense amplifier then sees this change,  

amplifies it and drives the bitline voltage down 

to 0 volts or ground. The sense amplifier is  

necessary because the capacitor is so small, 

and the bitline is rather long, and thus the  

capacitor needs to have an additional component 

to sense and amplify whatever value is stored.   

Now, all 8000ish bitlines are driven to 1 

volt or 0 volts corresponding to the stored  

charge in the capacitors of the activated 

row, and this row is now considered open.   

Next, the column select multiplexer uses 

the 10-bit column address to connect the  

corresponding 8 bitlines to the read 

driver which then sends these 8 values  

and voltages over the 8 data wires to the CPU. 

Writing data to these memory cells is similar  

to reading, however with a few key differences.

First the write command, address, and 8 bits to  

be written are sent to the DRAM chip. Next, just 

like before the bank is selected, the capacitors  

are isolated, and the bitlines are precharged 

to .5 volts. Then, using a 16-bit address,  

a single row is activated, the capacitors perturb 

the bitline, and the sense amplifiers sense this  

and drive the bitlines to a 1 or 0 thus opening 

the row. Next the column address goes to the  

multiplexer, but, this time, because a write 

command was sent, the multiplexer connects the  

specific 8 bitlines to the write driver which 

contains the 8 bits that the CPU had sent along  

the data wires and requested to write. These 

write drivers are much stronger than the sense  

amplifier and thus they override whatever voltage 

was previously on the bitline, and drive each of  

the 8 bitlines to 1 volt for a 1 to be written, 

or 0 volts for a 0. This new bitline voltage  

overrides the previously stored charges or values 

in each of the 8 capacitors in the open row,  

thereby writing 8 bits of data to the memory 

cells corresponding to the 31-bit address. 

Three quick notes. First, as a reminder, writing 

and reading happens concurrently with all the 4  

chips in the shared memory channel, using 

the same 31-bit address and command wires,  

but with different data wires for each chip.  

Second, with DDR5 for a binary 1 the voltage  

is actually 1.1 volts, for DDR4 it’s 1.2 volts, 

and prior generations had even higher voltages,  

with the bitline precharge voltages being 

half of these voltages. However, for DDR5,  

when writing or refreshing a higher voltage, 

around 1.4 volts is applied and stored in each  

capacitor for a binary 1 because charge leaks 

out over time. However, for simplicity, we’re  

going to stick with 1 and 0. Third, the number 

of bank groups, banks, bitlines and wordlines  

varies widely between different generations 

and capacities but is always in powers of 2. 

Let’s move on and discuss the third operation 

which is refreshing the memory cells in a bank.   

As mentioned earlier, the transistors used to 

isolate the capacitors are incredibly small,  

and thus charges leak across the channel. The 

refresh operation is rather simple and is a  

sequence of closing all the rows, precharging 

the bitlines to .5 volts, and opening a row.   

To refresh, just as before, the capacitors perturb 

the bitlines and then the sense amplifiers drive  

the bitlines and capacitors of the open row fully 

up to 1 volt or down to 0 volts depending on the  

stored value of the capacitor, thereby refilling 

the leaked charge. This process of row closing,  

precharging, opening, and sense amplifying happens 

row after row, taking 50 nanoseconds for each row,  

until all 65 thousandish rows are refreshed 

taking a total of 3 milliseconds or so to  

complete. The refresh operation occurs 

once every 64 milliseconds for each bank,  

because that’s statistically below the 

worst-case time it takes for a memory  

cell to leak too much charge to make a stored 1 

turn into a 0, thus resulting in a loss of data. 

Let’s take a step back and consider the 

incredible amount of data that is moved  

through DRAM memory cells. These banks of memory 

cells handle up to 4 thousand 8 hundred million  

requests to read and write data every second 

while refreshing every memory cell in each  

bank row by row around 16 times a second. 

That’s a staggering amount of data movement  

and illustrates the true strength of computers. 

Yes, they do simple things like comparisons,  

arithmetic, and moving data around, but 

at a rate of billions of times a second.  

Now, you might wonder why computers 

need to do so much data movement. Well,  

take this video game for example. You have obvious 

calculations like the movement of your character  

and the horse. But then there are individual 

grasses, trees, rocks, and animals whose  

positions and geometries are stored in DRAM. 

And then the environment such as the lighting  

and shadows change the colors and textures of the 

environment in order to create a realistic world. 

Next, we’re going to explore breakthroughs and 

optimizations that allow DRAM to be incredibly  

fast. But, before we get into all those 

details, we would greatly appreciate it  

if you could take a second to hit that like 

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and type up a quick comment below, as it helps get 

this video out to others. Also, we have a Patreon  

and would appreciate any support. This is our 

longest and most detailed video by far, and we’re  

planning more videos that get into the inner 

details of how computers work. We can’t do it  

without your help, so thank you for watching and 

doing these three quick things. It helps a ton. 

The first complex topic which we’ll explore 

is why there are 32 banks, as well as what the  

parameters on the packaging of DRAM are.  

After that, we’ll explore burst buffers,  

sub-arrays, and folded DRAM architecture 

and what’s inside the sense amplifier. 

Let’s take a look at the banks. As 

mentioned earlier opening a single  

row within a bank requires all these 

steps and this process takes time.

However, if a row were already open, we 

could read or write to any section of  

8 memory cells using only the 10-bit 

column address and the column select  

multiplexer.  When the CPU sends a read or 

write command to a row that’s already open,  

it’s called a row hit or page hit, and this 

can happen over and over. With a row hit,  

we skip all the steps required to open a row, and 

just use the 10-bit column address to multiplex a  

different set of 8 columns or bitlines, connecting 

them to the read or write driver, thereby saving  

a considerable amount of time. A row miss is 

when the next address is for a different row,  

which requires the DRAM to close and isolate the 

currently open row, and then open the new row.  

On a package of DRAM there are typically 4 numbers 

specifying timing parameters regarding row hits,  

precharging, and row misses. The first number 

refers to the time it takes between sending an  

address with a row open, thus a row hit, to 

receiving the data stored in those columns.   

The next number is the time it takes to open 

a row if all the lines are isolated and the  

bitlines are precharged. Then the next number 

is the time it takes to precharge the bitlines  

before opening a row, and the last number is 

the time it takes between a row activation and  

the following precharge. Note that these 

numbers are measured in clock cycles.   

Row hits are also the reason why the address is 

sent in two sections, first the bank selection and  

row address called RAS and then the column address 

called CAS. If the first part, the bank selection  

and row address, matches a currently open row, 

then it’s a row hit, and all the DRAM needs is the  

column address and the new command, and then the 

multiplexer simply moves around the open row.   

Because of the time saving in accessing an 

open row, the CPU memory controller, programs,  

and compilers are optimized for increasing the 

number of subsequent row hits. The opposite,  

called thrashing, is when a program jumps around 

from one row to a different row over and over,  

and is obviously incredibly inefficient 

both in terms of energy and time.   

Additionally, DDR5 DRAM has 32 banks for 

this reason. Each bank’s rows, columns,  

sense amplifiers and row decoders operate 

independently of one another, and thus multiple  

rows from different banks can be open all at the 

same time, increasing the likelihood of a row hit,  

and reducing the average time it takes for the CPU 

to access data. Furthermore, by having multiple  

bank groups, the CPU can refresh one bank in each 

bank group at a time while using the other three,  

thus reducing the impact of refreshing. 

A question you may have had earlier is why  

are banks significantly taller than they are 

wide? Well, by combining all the banks together  

one next to the other you can think of this chip 

as actually being 65 thousand rows tall by 262  

thousand columns wide. And, by adding 31 equally 

spaced divisions between the columns, thus  

creating banks, we allow for much more flexibility 

and efficiency in reading, writing and refreshing. 

Also, note that on the DRAM packaging are 

its capacity in Gigabytes, the number of  

millions of data transfers per second, which 

is two times the clock frequency, and the peak  

data transfer rate in Megabytes per second.

The next design optimization we’ll explore  

is the burst buffer and burst length. Let’s add a 

128-bit read and write temporary storage location,  

called a burst buffer to our functional diagram.  

Instead of 8 wires coming out of the multiplexer,  

we’re going to have 128 wires that connect 

to these 128-bit buffer locations. Next  

the 10-bit column address is broken into two 

parts, 6 bits are used for the multiplexer,  

and 4 bits are for the burst buffer. 

Let’s explore a reading command. With  

our burst buffer in place, 128 memory cells and 

bitlines are connected to the burst buffer using  

the 6 column bits, thereby temporarily loading, 

or caching 128 values into the burst buffer.   

Using the 4 bits for the buffer, 8 quickly 

accessed data locations in the burst buffer  

are connected to the read drivers and the data is 

sent to the CPU. By cycling through these 4 bits,  

all 16 sets of 8 bits are read out, and thus the 

burst length is 16. After that a new set of 128  

bitlines and values are connected and loaded 

into the burst buffer. There’s also a write  

burst buffer which operates in a similar way.

The benefit of this design is that 16 sets of  

8 bits per microchip, totaling 1024 bits, can be 

accessed and read or written extremely quickly,  

as long as the data is all next to one 

another, but at the same time we still  

have the granularity and ability to access any 

set of 8 bits if our data requests jump around. 

The next design optimization is that this bank 

of 65536 rows by 8192 columns is rather massive,  

and results in extremely long wordlines and 

bitlines, especially when compared to the size of  

each trench capacitor memory cell. Therefore, 

the massive array is broken up into smaller  

blocks 1,024 by 1,024, with intermediate 

sense amplifiers below each subarray,  

and subdividing wordlines and using a hierarchical 

row decoding scheme. By subdividing the bitlines,  

the distance and amount of wire that each tiny 

capacitor is connected to as it perturbs the  

bitline to the sense amplifier is reduced, and 

thus the capacitor doesn’t have to be as big. By  

subdividing the wordlines the capacitive load from 

eight thousandish transistor gates and channels is  

decreased, and thus the time it takes to turn on 

all the access transistors in a row is decreased. 

The final topic we’re going to talk about is 

the most complicated. Remember how we had  

a sense amplifier connected to the bottom of 

each bitline? Well, this optimization has two  

bitlines per column going to each sense amplifier 

and alternating rows of memory cells connected to  

the left and right bitlines, thus doubling the 

number of bitlines. When one row is active,  

half of the bitlines are active while the other 

half are passive and vice versa when the next row  

is active.  Moving down to see inside the sense 

amplifier we find a cross-coupled inverter. How  

does this work? Well, when the active bitline is 

a 1, the passive bitline will be driven by this  

cross-coupled inverter to the opposite value 

of 0, and when the active is a 0, the passive  

becomes a 1. Note that the inverted passive 

bitline isn’t connected to any memory cells,  

and thus it doesn’t mess up any stored data. The 

cross-coupled inverter makes it such that these  

two bitlines are always going to be opposite 

one another, and they’re called a differential  

pair. There are three benefits to this design.  

First, during the precharge step, we want to bring  

all the bitlines to .5 volts and, by having a 

differential pair of active and passive bitlines,  

the easiest solution is to disconnect the cross 

coupled inverters and open a channel between the  

two using a transistor. The charge easily 

flows from the 1 bitline to the 0, and they  

both average out and settle at .5 volts.  

The other two benefits are noise immunity,  

and a reduction in parasitic capacitance of the 

bitline. These benefits are related to that fact  

that by creating two oppositely charged electric 

wires with electric fields going from one to  

the other we reduce the amount of electric fields 

emitted in stray directions and relatedly increase  

the ability of the sense amplifier to amplify 

one bitline to 1 volt and the other to 0 volts.   

One final note is that when discussing DRAM, 

one major topic is the timing of addresses,  

command signals and data, and the related 

acronyms DDR or double data rate, and SDRAM,  

or Synchronous DRAM. These topics were omitted 

from this video because it would have taken an  

additional 15 minutes to properly explore.  


pretty much it for the DRAM, and we are grateful 

you made it this far into the video. We believe  

the future will require a strong emphasis on 

engineering education and we’re thankful to all  

our Patreon and YouTube Membership Sponsors 

for supporting this dream. If 

you want to  

support us on YouTube Memberships, or Patreon, 

you can find the links in the description.  

A huge thanks goes to the Nathan, Peter, and 

Jacob who are doctoral students at the Florida  

Institute for Cybersecurity Research for helping 

to research and review this video’s content! They  

do foundational research on finding the weak 

points in device security and whether hardware  

is compromised. If you want to learn more about 

the FICS graduate program or their work, check out  

the website using the link in the description.

 This is Branch Education, and we create 3D  

animations that dive deep into the technology that 

drives our modern world. Watch another Branch  

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