Question Increased IPC vs High Resolution

[KHansen]

Does increased IPC makes any difference, even when the GPU is the bottleneck at 3440x1440p in gaming?

 

[13thmonkey]

IPC itself doesn't really do anything, IPC x clockspeed = single thread speed.

So a better single thread speed and more cores might give you a smoother experience if the GPU is the constraint.

 

[KHansen]

IPC itself doesn't really do anything, IPC x clockspeed = single thread speed.

So a better single thread speed and more cores might give you a smoother experience if the GPU is the constraint.

So we are not talking about, a dramatic increase in performance then?

 

[13thmonkey]

not if you are GPU constrained. 1080p 144hz is a different story, there is the CPU power is important.

 

[hftvhftv]

Yes it does make a difference, but it is less pronounced as GPUs are usually under extreme load at 4K resolution.

 

[-Fran-]

Haha, this is a tricky question, but an interesting one.

My short answer is: yes, it does make a difference.

A CPU with strong IPC, across similar speeds with other CPUs, will indeed net you more FPS with a GPU using 100% processing at a given resolution.

Why? Because speed becomes less relevant. If the CPU can keep the GPU fed for a certain resolution, giving it more speed won't make the GPU consume/process frames any faster, but it will have room for other stuff to be done at any given speed. There's clearly a "baselined" speed to have depending on the uArch, but past that umbral speed, the frames won't increase and only IPC will help squeeze a bit more FPS'es. This may sound counter-intuitive, but the proof is in the pudding*. Compare AMD's FX line to any Core i family member across the board. FX does not get as many FPS'es per % clock increase as the Core i uArchs.

Cheers!

 

[InvalidError]

When the GPU is already at 100% load, there isn't much that a faster CPU can do to push even more frames through an already maxed-out GPU. You are trying to squeeze water out of a rock at that point, improvements will be between slim to none.

 

[mdd1963]

Does increased IPC makes any difference, even when the GPU is the bottleneck at 3440x1440p in gaming?

If anything (generally speaking) the higher the res/detail (such as 4K) the less a CPU matters as the GPU is often severely restricted...to an extent.

Naturally, I'd not be expecting a Ryzen 3-2200G to keep pace w/ a 9900K when both are given 2080Ti GPUs, as difficult a combination as that is to ponder...; but, R5-2600X could very well match the 9900K in many GPU-limited 4K gaming scenarios...

 

[InvalidError]

If anything (generally speaking) the higher the res/detail (such as 4K) the less a CPU matters as the GPU is often severely restricted...to an extent.

The CPU always matters about the same for a given FPS target in any given scene of any given title since little to no stuff in the game's core logic (where the CPU bottleneck usually is) knows about resolution and details. Given an infinitely powerful GPU, you will always need approximately the same amount of CPU-power regardless of details and resolution since those are almost entirely for the GPU to deal with.

If you need an i5-8600k overclocked to 4.5GHz to achieve stable 1080p144 Low in a given scene, you will still need the same i5 or slightly better for stable 8k144 Ultra should a sufficiently powerful GPU ever become available.

If you meant "less important" as in as a proportion of total build cost, then sure, higher resolution puts more pressure on the GPU budget and makes the CPU a smaller chunk of the bottom line, especially if you decide to give up one CPU tier to go up one GPU tier along the way - no point in having a CPU that could push 240Hz if the best GPU you can afford after spending $600 on the CPU can only do 100Hz at your desired resolution and details. Unless the GPU is temporary or you need the ludicrously expensive CPU for other stuff.