While the average frame rate is the same, you see more stutters as the CPU chokes on feeding the GPU in certain cases. So the max frame time is much longer.

At least that’s what I saw on my [email protected] before upgrading to a 1700X@4GHz with the same 1080 GTX running mostly at 4k.

It seems like while the per-core IPC was mostly similar, maybe 10-20% different, the peak memory bandwidth was bottlenecking me.

The lower bounds is where it makes a big difference for most people who are GPU bound at the top end. The 1% and 0.1% of slowest frames when playing a game show huge differences based on CPU and RAM. For the smoothest gaming you need to remove all the potential bottlenecks of the system thats one of the reasons gaming has always pushed the boundaries on CPU/GPU.

it's not that relevant. There are virtually no plausible gaming setups where you'd be likely to actually notice the differences where intel actually wins. You need a very fast GPU, high fps screen, specific games, large differences (because 100fps vs. 150fps is much, much harder to see than say 40 vs. 60 fps), low resolution+settings, and few enough background programs that you don't cause issues on that side.

It's measurable sure; but it's not relevant practically no (at least, the 9900k vs. 3900x decision isn't; you will perhaps notice a little more easily the upgrade all the way back from sandy bridge... but even that...)

I was doubting this for a while but there are finally games now that will bottleneck a 2012 era CPU. I’m planning a Ryzen upgrade for this purpose.

Oh, which games? The part of me who's still a child is looking for a GOOD reason to justify the spending to the part of me who is now a responsible adult (and to my SO).

Not even super new games, but games like Deus Ex Mankind Divided and No Mans Sky have better frame rates on my buddy's Ryzen 2 machine with otherwise identical specs than my i5 3450.

The first game where I saw the difference was Battlefield 1.

I think a lot of cross platform games have been optimised to use lots of CPU cores, since the modern consoles currently have 8. If you're running an older CPU with less cores, even if they're more powerful, you're starting to see performance drags, that was especially the case for BF1.

I'm seeing people's upgrade paths and I feel kinda guilty for holding on to my i5-2400 for that long...

Don't feel that way at all, if anything I should feel guilty for thinking of upgrading!

I'm probably going to survey the market early next summer before Cyberpunk.

I feel with you, but honestly: If that machine is fast enough, why care? ;-)

Read up about 1% and 0.1% slowest frame rates, it's a somewhat unknown metric but makes a big difference in the immersion of a game.