128 Bit Vs 256 Bit GPU: All Differences (Detailed Guide)

A lot of people are confused about the difference between a 128 bit vs 256 bit gpu. This article will help you to understand the terminology, what it means for your current GPU, and how much more powerful your computer would be if it had a higher number.

128 bit vs 256 bit gpu Memory Bus Width

This is an easy one. The memory bus width is the number of bits your card uses to send and receive data from the main memory or VRAM. If a GPU has a 128 bit bus width this means that it can only send and receive data over 128 bits at a time. With higher numbers, like 256 bit, you will see an increase in performance with higher resolution textures, sharper shadows, and better anti-aliasing quality thanks to more available bandwidth which allows for more information to be sent to the GPU at once.

128 bit vs 256 bit gpu Information storage

Even though the information storage is usually measured in megabytes, you need to make sure that it matches up with your bus width or else you will have bandwidth issues which could result in dropped frames during intense moments. To calculate this number simply take your memory clock speed and divide by eight, then multiply that number by the amount of memory on your card (expressed in Megabytes).

Example: 400MHz Memory = 5GB/8 = .625 GB per cycle

So if I had a 128-bit GPU I would want my memory to be around 625MB/s however if I had a 256-bit GPU than 1125MB/s would be required. This can quickly get out of hand when you realize that most mid range GPUs from the past two years have been equipped with GDDR5 memories that run at around 1750MB/s. This means that a 128-bit GPU would be nearly 50% less efficient when compared to a 256-bit GPU even though they both have the same amount of memory.

128 bit vs 256 bit gpu Bandwidth

Now we finally get down to the nitty gritty since this is where all of our calculations will come together allowing us to see which card has superior performance under stress conditions.

In order to properly calculate bandwidth you need to take your bus width, multiply it by its data rate, then multiply that number again by two and voila! You now have total available throughput in Megabytes per second. The higher this number is the better your graphics rendering speed will be which means that you can have more objects on screen, higher resolutions, and smoother textures.

128 bit vs 256 bit gpu Resolution

This is just another way of saying pixel count since pixels are basically what everything is made up of when talking about graphical programs. Since having lots of pixels means that you need more available memory to store all those pixels regardless if they are being used or not it would be wise to have ram with high data rates so that the information can move across the bus as quickly as possible.

This leads us yet again back to bandwidth because this number tells us exactly how much data we can push through the GPU per second; the higher this number is, the better your performance will be.

128 bit vs 256 bit gpu Ideal resolution

Now that we have all of our numbers it’s time to match them up with what they pertain to. So basically if you had a 256-bit bus width running at 400MHz then your total available throughput would be 6,750MB/s (400 x 2 x 256).

This leaves us with the question of what kind of resolution is ideal for this type of GPU? Well since we know that the formula for calculating pixel count is simply width multiplied by height; in our case both are measured in bits so having 768 pixels in width and 768 in height would give us 576,932 pixels which is more than enough space to display an HD Ready (1280×720) image.

The reason that I chose to use bits instead of bytes (1,073,741,824 pixels) is because this number increases significantly when using 16 bit textures which can be used to greatly improve image quality.

128 bit vs 256 bit gpu DirectX support

In this category there is literally no difference between a 128 bit vs 256 bit gpu from any point of view, from drivers to memory bus sizes and shader processors. The DirectX support has absolutely nothing to do with the number written on the box so don’t be confused by marketing tactics trying to convince you otherwise.

128 bit vs 256 bit gpu Bus Width Ratio

The bus width ratio is not as easily defined as simply saying “this much”. This terminology actually includes many other things like RAM speeds (which are also measured in MHz), the actual bus width (the amount of data carried over 1 cycle of transfer), or even available power for overclocking.

You can think of it like your full pipe size to get water through your home’s plumbing system. If you have a quarter inch pipe and try to send gallons of water through it, it won’t work because there will be too much resistance in the pipes (and probably flooding).

The biggest differences between these two cards is how much more data they can push at once due to their bus widths. Like I mentioned above, 28 bit vs 256 bit gpu doesn’t tell the whole story because if one card has DDR5 memory while another has DDR3 than their effective speeds will be far different when put into practice.

128 bit vs 256 bit gpu Processing Power

The processing power of a GPU can be measured in many different ways. It may be the number of stream processors, the texture units, or even how fast it can process information like 32 bit vs 64 bit gpu (which is also completely different than your windows version).

Whether this number goes up or down depends heavily on what type of game you are playing. If you are looking for more power in video games where you need to render large amounts of 3d objects then look for an increased number here. For other types of games that require less computational horsepower than you should focus more on factors like memory speeds and bus widths to get better graphics without spending too much extra money.

128 bit vs 256 bit gpu Memory Bandwidth

This is one of the more important factors when considering a new GPU because it directly effects how many textures and other graphic elements your GPU can handle at once. You will see this reflected in things like texture resolution, anti-aliasing quality, and bloom lighting.

This is just a fancy way of saying that if you have DDR5 memory on your 256 bit gpu then you will be able to send up to 5 pieces of data across the bus at once (if all 4 bits are carrying data) compared to only 1 for the 128 bit counterpart. The extra bandwidth allows for better picture quality and more objects on screen but there is still another bottleneck between memory speed and total performance which we will discuss further down.

128 bit vs 256 bit gpu Fill-rate

Fill-rate is related to the bus width because it measures how much data can be pushed through the pipe in one second. If you have a car driving on a highway and there are cars stacked up at an intersection then that traffic has to wait to get through, but if that same road had 3 lanes (or twice as many) then cars would be able to pass through faster. This seems like it may seem unrelated but it can actually affect your framerate by limiting the speed of your GPU drawing different items on screen. By increasing this number with better hardware you can increase performance without changing other things which will also give you better picture quality.

128 bit vs 256 bit gpu Shader Processors

The shader processors are what allow for many of the special effects you see in games like anti-aliasing, depth of field, and high quality lighting. This number will heavily depend on whether your game is made with DirectX 9 or 11 in mind so if you have one type or another then this will limit which cards are available to you. The general rule here is that the more shader processors there are, the better it will be able to handle lower resolution textures without sacrificing too much performance.

Atomisiing rendering takes a lot of computing power and often only 1 model can be rendered at any given time so having more shaders allows for better picture quality when multiple objects are being rendered at once. Like I mentioned above, having a high amount of shaders doesn’t automatically mean that your picture quality will be better it just means that you have more chances to get a high-quality render out.

This may not be noticeable from afar or when moving around in the game but it is still an important factor for consideration.

128 bit vs 256 bit gpu RAM Speeds

The ram speeds on a GPU can make a huge difference in how fast textures load and other graphic elements are processed. While this number does play a part in determining bandwidth, you also need to consider the bus widths between the memory and processor within the GPU itself which we discussed earlier.

For many games this won’t make much of a difference but some games will have a bottleneck that limits the effective speed of this type of data transfer. If you are playing games that tend to have more high-resolution textures then it is important to consider using ram with lower latencies and faster memory speeds. If you are not familiar with these terms than just try to look for DDR5 on your memory rather than DDR3 because it will make your GPUs overall performance better even if the bandwidth is technically 133mhz higher (on average).

128 bit vs 256 bit gpu Core Clock Speed

Once upon a time, there was no difference between the core clock speed on most GPUs besides its operating system version (i.e. Windows 7, Vista, etc.). However now Nvidia has started making separate ‘overclocked’ versions of their GPUs on specific models and on some of them there can be a huge difference in clock speeds.

The general rule of thumb here is to look for higher core clock speeds on the more expensive cards since they tend to come with better performance overall (but you still need to check for other factors like bus widths, memory speeds, shader processors, etc. as well). Even if you don’t plan on ‘overclocking’ your GPU it is important to remember that higher frequencies usually allow for better menu navigation and information processing which results in smoother performance and less stuttering during intense moments.

128 bit vs 256 bit gpu Shader Clock Speed

This number will not only effect how many shaders your GPU processes but also (to a much smaller degree) how fast those shaders process the data. The shader clock speed is basically how many operations per second your GPU can do and this doesn’t really apply to the layman since you already have all of these specifications written out for you on store shelves. This one will mainly determine theoretical performance (which we will discuss next) but it still plays an important role in determining quick responsiveness times for objects within games.

128 bit vs 256 bit gpu Theoretical Performance

This is by far the most complicated factor you need to pay attention to when looking at different GPUs because it requires some research before purchasing. The theory behind finding this number is simple: You take the number of shader processors, multiply that by the clock speed of the shader processors, then multiply that by the number of bits for memory bandwidth. If you are still confused than just keep reading and I’ll do my best to explain it all in more detail below.

Shader Processors*(Core Clock Speed)*(Data Rate) = Theoretical Performance

128 bit vs 256 bit gpu Processor Frequency

Finally we have the processor frequency which is measured in MHz like all other ram and processors. This number tells us how fast a GPU can compute an instruction. Higher numbers here will speed up your games and graphical programs allowing for faster rendering, lower latency, and better performance overall.

You might think that if a card contains a 256-bit bus width then it would be better than a 128-bit card with double the throughput but this isn’t always true because having a wider bus isn’t always better unless your bandwidth matches up with that of your memory

When you are talking about the bus width, it refers to how much information can travel at one time across the chip. This is usually quoted in bits because the faster processor speeds are being measured in billions of cycles per second, or gigahertz.

128 bit vs 256 bit gpu Cuda cores

This is basically how many cores are being used to calculate the 3D environment and can be referred to as ‘general processing power’. The more cores your GPU has, the more efficiently and quickly it will be able to render (or compute) data. Now we know that we need to make sure this number matches up with our processor frequency but what exactly does that entail?