Buying a new graphics card is one of the greatest joys of owning a gaming or other high-performance PC. You can take a computer you own and upgrade it to modern graphics standards for a fraction of the cost of the entire machine.
Unfortunately, while your GPU is a key component of gaming performance, it doesn’t work in isolation. It depends on the other components of the computer to do their job properly, otherwise it won’t be able to reach its full potential. This is called a bottleneck and is a key consideration when buying a new GPU. In particular, the bottleneck between your GPU and your existing CPU is a major issue.
Fortunately, there are several online tools to help you identify bottlenecks and make your decision based on them. Specifically, we’ll take a look at a comprehensive tool that can be found at gpucheck.com
Before diving into the actual steps required to determine if a bottleneck exists between your existing processor and your intended GPU, we need to briefly understand what the bottleneck is from a practical standpoint.
What is the real GPU and CPU bottleneck?
What exactly is the GPU-CPU bottleneck?
When you play a video game, every component of your computer works on some aspect of the entire system. Your CPU is usually responsible for doing physics calculations, thinking for game AI, running game logic, driving animations, and so on. Your GPU renders all the visuals you see, including all the geometric wireframes, textures wrapped around them, lighting, and shadows.
It is clear that the GPU cannot render a given frame of the game if the CPU has not completed the necessary calculations. If your character has thrown a knife at a goblin’s head, the GPU will not be able to reflect the blow unless the processor tells him if the knife has hit the target!
The converse is also true. If the CPU has finished its calculations, but the GPU hasn’t finished rendering the previous frame, the CPU should wait for this, possibly even resetting it because it is no longer up to date.
In a situation where one component is waiting for another to finish its work before continuing its work, you have a bottleneck. In fact, the entire system only works as fast as the slowest component in the chain. In video games, this usually results in the frame rate being limited by the slower component.
Are the bottlenecks in general serious?
Are bottlenecks bad globally?
No! In fact, on any system there is almost always a bottleneck. It is very rare that any computer can be perfectly balanced in every situation where every component is operating at full capacity. So the problem is not whether there is a bottleneck, but whether the problem is limiting the performance of slower components.
If your CPU only benefits from 98% or 99% of your GPU’s maximum performance, this is hardly a problem. If, because of a slow processor, you’re only using 70% of your GPU’s potential, you’ve wasted money on hardware performance that you can’t access without another upgrade.
If your new GPU is 100%, but your CPU is only 50% utilized, that means you could plug in a faster card and enjoy even better performance. However, this situation is less of a problem, given that we usually use our computers for other tasks than just playing games.
So for other applications, you will still take advantage of this spare CPU power. Not to mention, you have room to do additional background tasks without affecting game performance. In short, the GPU bottleneck is good, the CPU bottleneck is bad.
Additional factors influencing bottleneck interpretation
Additional factors that influence bottleneck interpretation
Interpreting the severity of bottlenecks is more than simply saying that GPU X and CPU Y are a bad match. This is because different types of software put a different load on each component.
A game that uses only minor processor features will allow your GPU to fly at whatever frame rate it can control. On the other hand, load up a CPU intensive simulation or strategy game and suddenly your normally underutilized CPU drops your frame rate instead.
The settings you use for the game also affect this calculation. For example, playing at a higher resolution increases the load on the GPU, slowing it down because it takes longer to process more pixels. The higher the resolution, the less bottleneck the processor becomes.
Because it still does the same job, but the GPU does more. So if your CPU is limiting your frame rate to 60fps when playing back at 1080p, you will still get 60fps at 1440p or 4K if your GPU is up to it.
Checking bottlenecks with GPU check
Check for bottlenecks with GPU scan
Now that we have a preamble, let’s really do a virtual bottleneck test.
- First go to this page when checking the GPU. Now, in the first combination, select the GPU you have as well as the CPU you have.
- For the desired quality setting, we will leave it at ultra, since this is the setting we want to use in games. If you’re aiming for something lower, adjust accordingly.
- Now, under the second combination, select the GPU you are going to buy. Finally, click on “Use the same processor”.
- Then click Compare.
Let’s take a look at the results and interpret them. The most important metric here is the impact of the processor on FPS. This shows how much the CPU is holding back the GPU. With the old card, this figure was 10%, which is considered normal, although preferably less.
New card slows down 20% CPU. This means we are probably better off buying a slightly slower card, overclocking the existing CPU, or upgrading the CPU later.
Of course, in real terms, this new GPU is between 36% and 39% of our current combination. The overall combination score shows us how good this combination of absolute performance is at ultra settings.
Using this information, you can make an informed choice as to whether this future graphics card is right for you.