Can high-end GPU choke low-end CPU?

[nillawafers]

I know this might be a weird question since it's usually the other way around, but I was wondering if a high-end GPU could choke a low-end CPU since we know the inverse is true?

For example, I have an R9 290X with a G3258 CPU overclocked to 4.0GHz. While playing Shadow of Mordor, occasionally (more often than I'd like to be honest) the CPU usage will spike to 100% and I will get stuttering. Otherwise, it runs at 55-60 FPS most of the time with my CPU load around 85-95%

However, I was looking at other people's gameplay, and on some people's machines, they would be running an R9 270 with the G3258 at stock speeds - 3.2 GHz - and they would not get any stuttering or CPU spikes. However, their FPS was also around 35-40 most of the time with CPU load of 60-70%.

So, do lower-en GPUs give more consistent performance at the cost of total performance when it comes to low-end CPUs even when the game is at comparable settings?

This is mostly out of curiosity.

 

[cbn]

Yes.

 

[nillawafers]

Yes.

So, if I were to switch to a worse-performing GPU, there would also be less stress on my CPU, which would alleviate spikes/stutters but give worse performance?

 

[amenx]

I know this might be a weird question since it's usually the other way around, but I was wondering if a high-end GPU could choke a low-end CPU since we know the inverse is true?

For example, I have an R9 290X with a G3258 CPU overclocked to 4.0GHz. While playing Shadow of Mordor, occasionally (more often than I'd like to be honest) the CPU usage will spike to 100% and I will get stuttering. Otherwise, it runs at 55-60 FPS most of the time with my CPU load around 85-95%

However, I was looking at other people's gameplay, and on some people's machines, they would be running an R9 270 with the G3258 at stock speeds - 3.2 GHz - and they would not get any stuttering or CPU spikes. However, their FPS was also around 35-40 most of the time with CPU load of 60-70%.

So, do lower-en GPUs give more consistent performance at the cost of total performance when it comes to low-end CPUs?

This is mostly out of curiosity.

I doubt it. Might be be other issues or variables causing that.

 

[aaksheytalwar]

Yes. A more apt GPU might help reduce the stuttering. But this only happens when there is a significant mismatch.

I would recommend trying to limit the FPS and under lock and underpower the card before you sell it.

 

[parvadomus]

So, if I were to switch to a worse-performing GPU, there would also be less stress on my CPU, which would alleviate spikes/stutters but give worse performance?

No. Independently from the GPU the CPU always has to do the same work. If you switch to a worse GPU, you will continue with the spikes, but add to that a lower average framerate.
There is a difference between vendors however. Nvidia cards seem to put less stress on CPU, or at least utilize it better (by having multithreaded drivers or by implementing NVapi or just by game optimizations). There are scenarios where AMD is better, like games that support Mantle or when you have a low core count (dual core) CPU.

 

[gamervivek]

It could be the case that the GPU driver is 'heavier' for the better card. Or they're running at different settings that cause more cpu load.

 

[lehtv]

How much RAM do you have?

 

[SPBHM]

something that might help in this situation is to use an artificial max FPS lock,
like if you set it at 30FPS max

 

[Flapdrol1337]

So, if I were to switch to a worse-performing GPU, there would also be less stress on my CPU, which would alleviate spikes/stutters but give worse performance?

Yes.

But it's easier to run an fps limiter or force a gpu limit by using something like VSR.

 

[bystander36]

Yeah, a higher resolution, higher settings or higher AA can put the GPU to work and prevent the CPU to be pushed to its breaking point.

I'd also point out, this may be more of an issue of your 2 core CPU, than the speed. When pushed to the limit, due to not having more threads to use for small needed processes, it uses a core that is pushed to its limit.

 

[Yuriman]

Some graphical settings require more CPU power. So, by running a GPU that can handle those settings, you may inadvertently increase CPU load too.

A GPU won't increase load in and of itself.

 

[bystander36]

Some graphical settings require more CPU power. So, by running a GPU that can handle those settings, you may inadvertently increase CPU load too.

A GPU won't increase load in and of itself.

If the GPU allows for higher FPS, that increases CPU load.

 

[Yuriman]

If the GPU allows for higher FPS, that increases CPU load.

Well, sure. But you can achieve the same framerates on a lower-end GPU by simply lowering some graphical settings. It's not like it's impossible to get 60fps on a low-end card.

 

[cbn]

So, if I were to switch to a worse-performing GPU, there would also be less stress on my CPU, which would alleviate spikes/stutters but give worse performance?

http://www.eurogamer.net/articles/digitalfoundry-2014-pentium-g3258-review

In the highlighted video, you can see that running the game at the high preset (that's one 'notch' down from the ultra-equivalent, very high) in combination with a GTX 760 results in a night-and-day performance differential between the i7 4790K and the Pentium. The additional fidelity in the game simulation, coupled with the immense increase in GPU set-up costs, sees the Anniversary Edition Pentium struggle horrendously to keep pace. What we're seeing here is a classic case of a lack of hardware balance: the G3258 simply can't feed the GTX 760 quickly enough to sustain a consistent frame-rate.

Now, compare and contrast with the secondary analysis, where we drop the GPU down to a far more modest GTX 750 Ti, and lower the overall quality preset to the medium level. In this case, for the most part it is the graphics card that is the bottleneck, and the overall performance level lowers the i7 advantage significantly.

Also, I liked Flapdrol's post here:

http://forums.anandtech.com/showpost.php?p=37502538&postcount=22

Pentium has run every game I tried very well.

If you're not gpu limited you have to sometimes use an fps cap though. Otherwise the high priority game threads hog both cores until the background/low priority threads can't be delayed anymore, and you get noticable stutters, or even have the game stall for a second.

Anyway, I have a gtx 670 so I don't often have to do that.

In a nutshell, get a smaller card and lower detail settings in order to smooth out gameplay.

 

[bystander36]

Well, sure. But you can achieve the same framerates on a lower-end GPU by simply lowering some graphical settings. It's not like it's impossible to get 60fps on a low-end card.

The point is, a faster GPU will increase the CPU load when using the same settings.

 

[Yuriman]

The point is, a faster GPU will increase the CPU load when using the same settings.

But when targeting the same framerate, CPU load is generally the same (aside from a few graphical settings that increase CPU load themselves). I suspect most people adjust their settings to get to a desired framerate.

When I upgrade my GPUs, it's not because my framerates are getting too low. Rather, it's because the settings I have to pick to achieve my desired framerates are getting too low.

 

[bystander36]

But when targeting the same framerate, CPU load is generally the same (aside from a few graphical settings that increase CPU load themselves). I suspect most people adjust their settings to get to a desired framerate.

When I upgrade my GPUs, it's not because my framerates are getting too low. Rather, it's because the settings I have to pick to achieve my desired framerates are getting too low.

You are making an assumption. That works out more often at the low and mid ranged GPU's, but at the high end, people often find themselves not needing to lower settings at all. Low GPU demanding games will put you there more often as well.

But if you do play at a specific frame rate, I would most agree. You just can't assume that a faster GPU is going to be reduced to the same frame rate, as the OP has demonstrated.

 

[Yuriman]

You are making an assumption. That works out more often at the low and mid ranged GPU's, but at the high end, people often find themselves not needing to lower settings at all. Low GPU demanding games will put you there more often as well.

But if you do play at a specific frame rate, I would most agree. You just can't assume that a faster GPU is going to be reduced to the same frame rate, as the OP has demonstrated.

In OP's case, lower end cards compared are getting 30-40fps, while OP is shooting for 55-60. If OP increased graphical settings or capped framerates to 30-40, stuttering wouldn't happen. If the R270 systems lowered their graphical settings so that they were able to obtain 55-60fps, I imagine they'd have stuttering too.

The problem here is that in order to get 55-60fps, the Pentium simply isn't sufficient, regardless of the GPU. (Or, well, an NV card might or might not be better, but that's a different set of drivers)

 

[biostud]

Basically 2c/4t is minimum for top games. A 2c/2t CPU simply chokes on high settings. That's why a lower clocked i3 often performs better than a higher clocked Pentium.

 

[Gonad the Barbarian]

Good god this thread hurts to read. No, you will not get better performance from a weaker card. If you could, just downclocking the card you have would get you there. If your framerate stutters while your CPU hits 100% you've got a plain old CPU bottleneck. Change graphic settings or look for something leeching cycles in the background, this game is pretty forgiving on hardware. Or you can cap your frames at the point where your CPU bottoms out and have it that choppy the whole game.

If you haven't tried it yet, run in borderless window mode and see if it makes a difference.

 

[zir_blazer]

The stuttering caused by the Processor having 100% CPU usage spikes may not even be related to the game, it could be a background task. That's why it makes the game stuttering when that happens.

 

[KingFatty]

Is there any evidence/testing that isolates the notion that changing the graphics load can affect CPU burden?

Theoretically it makes sense that when you disable a "graphics" feature affecting the CPU, then the CPU will need to do less, easing the CPU burden slightly. But what about just changing resolutions, with all the features the same? How does that affect the CPU?

 

[Headfoot]

If your GPU can push more frames, then it can indirectly put load on the CPU up to its limit as the CPU becomes the bottleneck in completing frames.

Higher settings may also increase CPU load, and most of the time they do. Especially for settings that increase draw calls

 

[firewolfsm]

I've been curious about this because my XPS 13 has an i5-6200U and a thunderbolt 3 port I plan to use for to power an egpu. I'm wondering what's the highest reasonable GPU to use considering the CPU is 2c/4t and will run at a constant 2.7GHz.