He’s saying typically PCs don’t use much more memory bandwidth than 40Gb/s. You can only get so much bandwidth from DDR4.
but these console CPUs have access to much more bandwidth. So In theory they could compute more. For specific AVX workloads in the DS space it is sometimes faster to use AVX than it is the GPU. It just really depends on cache and fitting etc. In those cases your bandwidth may reach and be fed at higher levels than typically the norm for a CPU.
Exactly. Say, for instance that you have a game engine that does clever things leveraging the CPU, generating 1 GB/frame traffic over the memory bus. Well, on the consoles at 30fps that’s less than a tenth of the nominal bandwidth, so no problem. Even at 60fps you are perfectly fine albeit with a slightly compromised. bandwidth available to the GPU. No real problem though.
On a PC however, a good scenario today would be that the CPU was connected to dual channels of DDR4 3200, for a total nominal bandwidth of 51GB/s. You won’t ever reach that with actual game code, but the 30GB/s at 30 fps of our example should be OK. But as desired frame rates increase you run into a brick wall. No matter what graphics card you use, or what high frequency multi core CPU you own, you won’t get around your CPU bandwidth limitation. Throwing money on the PC-standard top of the line components won’t help you much in this case.
So if console frame rates are CPU processing limited, you will be hard pressed as a PC gamer to improve matters much beyond another 50% or so, but if the console CPU code uses even a relatively modest part of its available bandwidth, then you’re
really up shit creek if you want high frame rates.
And even five years from now, with 32core CPUs, DDR5 and RTX 5080Ti GPUs, that will still be true.
It’s a system wide architectural weakness of the PC platform.
Now, multiplatform titles will probably not utilize the console CPUs in such a way as to totally cripple PC port performance. But assuming that they will all use a tiny fraction of the bandwidth resources of the consoles, in order to facilitate running at 144+ frame rates on PCs with a tenth of the available bandwidth is probably not a good idea either.
(All in the Jensen context of 360fps gaming.)