So what would be the effect of a four core versus an eight core processor on the game. We'll test this with two graphics cards.
Above we have the Radeon RX 580, the effect of 4 versus 8 CPU cores really doesn't matter. Mainly because the radeoN RX 580 is GPU bound, meaning the effect of more threaded logical (or faster) CPU cores has much less of an effect. So lets take one of the most expensive graphics cards that your money can buy you, which is much more CPU bound, the Nvidia Titan X (Pascal).
So you can see a bit of an effect at 1080p, remember we are using very high quality for testing. At 1080p we see a 6~7% differential, that fades away one we go upwards in resolution. If we'd opt LOW or medium quality settings, the effect would be bigger.
AMD Ryzen 7 versus Intel Core i7
So for our next test I will be performing a 1:1 platform comparison in-between a Ryzen 7 (8-core) processor clocked at 4000 MHz on all cores. Then for Intel we do the same with the 5960X at 4000 MHz on all cores, here we'll simply look at platform performance difference based upon the same graphics card. Both systems have identical software abnd drivers installed.
So as you can see I clocked both platforms at 4.0 GHz to equalize and neutralize the proc clock frequency differences. Both are 8-core part with 16 threads. The AMD system uses the latest AGESA 1006 BIOS and has dual-channel 2933 MHz enabled. The Intel platform uses slightly slower 2400 MHz DIMMs, however that one has the advantage of quad-channel memory. The platform difference is only noticeable at a 1080p reolution with an ~10% difference. Let me reiterate that if you'd pick up a 329 USD Ryzen 7 1700 you'd get exactly the same results, the cheapest Intel 8-core part is roughly 1100~1200 USD.
You will only see this 1080p differential with enthusiast class graphics cards (we use the Titan X Pascal here). To show you that, we'll also perform this same test with a Radeon RX 580:
And yes the AMD platform was actually 1 FPS faster overall, pretty frickin nice value there eh? Everything is relative though as tweaking and overclocking (or faster clocked processors) do have an effect as well. Where Ryzen 8-core parts end at 4.0~4.1 GHz the Intel 8-core parts can go 4.3~4.4 GHz so they can potentially squeeze a little extra perf out of the game.