How does the CPU actually affect FPS

[UrbanGhetto]

Hey everyone,

 

So I'm running a GTX 760 by MSI with an Intel G3220 for about 2 months now, I had a low budget and I really wanted to put everything on the GPU since I heard here and there that the CPU really doesn't matter that much for gaming performances.

 

Every game works nicely I rarely went under 40 fps in gaming which really doesn't bother me at all, but now I'm curious, if I buy an i5 for example, will I get a big performance increase in gaming ? I know that this really depends from a game to another but is there a rule about it ? I mean for example does MMOs rely mostly on CPU and FPS on GPU for example ? How can I know that this game will be much better with a better CPU while having a big CPU on that other one is useless ?

 

Thanks for your future answers.

[Vacsol]

the G3220 may be bottlenecking your system.
Having a good GPU is important, but if you cheap out on everything else that's not going to be a good thing

The key to a good build is balance.

[Excon]

If you went to an i5 it would be more cores and more speed. Both of those would increase your fps

[Oshino Shinobu]

Pretty much all games will be more demanding on the GPU than the CPU, but some games use more CPU than others. Things like MMOs and AI heavy games can use a lot of CPU power. 

 

In terms of how it affects FPS... It's hard to explain. It depends on how much it's being used, so a very weak CPU that's at 100% load in a game, along with a 780 will be the limiting factor for the PC. Going to an 15 would increase your FPS as it will be able to keep up with the GPU better, but don't expect huge FPS jumps. 

[Clyne]

Well with a intel g3220 with have a bit of a bottle neck but if you want the best performance with your gtx 760 then get a amd fx 8320 or amd fx 8350 or i5 4670k or i5 4690k.

[D3MON]

It depends on the game (does noone see this in my sig?)
some games from 2005 are badly threaded and use core 0 and sometimes core 1 and dont care about this new fangled "multi-core" cpu thingy, most simple games like mmorpg's are like this.

modern games with modern game engines typically scale across cores to reduce cpu   limitations and fully enable the use of your gpu...as it should be. even minecraft and world of tanks can use 3-4 threads.
i personally limit my games to cores 4-7 and set other stuff like fraps to cores 0-3, my phenoms while badass could run any game i threw at  them on just 3 cores leaving me with 1 free but it limited me in recording a little.
my laptop/phone/server has a dual core and for that its fine but not in a beast system.

also xCPU +xGPU doesnt = bottleneck. you can have a pentium k with a r9-290x and so long as your playing those 2005 games you wont be bottlenecked per-se (you will no matter what you do in games like that but you'll still get 311fps).
however in a game like bf3 which is well threaded a pentium k will likely bottleneck any gpu upto a point where the gpu performance is so low its not worth playing anyway. (techspot cpu tests show this).

edit-flick through my "stuff" gallery if you wanna see screenshots and see which games are well threaded and gpu bound, most people that say "cpu heavy" dont know what they mean.

[UrbanGhetto]

Okay thanks for your answers, I thought about buying a new screen or one more HDD but after what you all told me I'm definitely gonna buy an i5 or i7 to avoid that bottlenecking thing.

 

Thank you again.

[Hieb]

Game engine, AI, and audio processing all eat up a certain amount of processing power. Beyond that, certain effects may use the CPU somewhat (such as complex explosions). For the most part the CPU just sends a certain amount of data to the GPU for every frame rendered. The CPU tells the GPU what to draw, and then the GPU does the grunt work.

 

CPUs are good enough at this point that you don't really need to spend that much for a decent gaming experience. Having a weak CPU generally you'll maintain roughly the same average framerates, but your highs won't be as high, and your lows will be a bit lower. In periods where there's a very heavy load on the CPU, that's when you would see benefit from an i5. Also if you wanted to play on a 120Hz monitor that's probably where you would run into the Pentium G3220 bottlenecking, because it can't process that many frames. This is why in CPU reviews often times they play at low resolutions like 1680x1050 or 1280x1024... beacuse this highlights the maximum possible performance of the CPU.

 

But if you only aim for 30-60 fps and ultra settings, a weak CPU is good enough. Higher resolutions, more detailed textures etc. are all demanding on the GPU but don't really task the CPU... the CPU basically just runs the game engine, audio, AI etc. and tells the GPU what it needs to draw for each frame. Lower framerate happens when the CPU is getting bogged down by a heavy workload and there's more delay for when it sends the GPU info for the frame.

 

So basically if a CPU is getting maxed out, then framerates will drop even if you have the best GPU on the block. Whereas if you aren't shooting for super high framerates and instead are focused on image quality and higher resolutions, CPU isn't all that critical.

 

The reason MMOs tend to benefit more from CPU is because there are very few that effectively use multi-threading, and they all depend on single-threaded performance... but they have a LOT going on at once, so it ends up overloading 1-2 cores and almost constantly maxing them out. So often times GPU doesn't seem as significant because the 1-2 cores that are being used are always maxed, so whether you have a GTX 760 or a GTX 780 Ti makes only a small difference because they're waiting on the CPU for frames since it's being maxed out.

 

To answer your other question, some games would benefit from an i5 significantly while others would see little benefit. Many single player games will probably perform close to identically as they do now, maybe a few fps better with the clock speed increase an i5 would bring... while stuff like BF4 multiplayer or something would benefit significantly since it eats up a ton of CPU. Especially if you wanted to get into 120Hz gaming.

[D3MON]

-snip-

this^, he's got a beard, beardy techy guys got us where we are today...look at Dennis Ritchie...