Because PCIe bandwidth is higher than memory bandwidth This doesn't sound right, a PCIe 5.0 x16 slot offers up to 64 GB/s. That's fully saturated, a fairly old

Because PCIe bandwidth is higher than memory bandwidth This doesn't sound right, a PCIe 5.0 x16 slot offers up to 64 GB/s. That's fully saturated, a fairly old Xeon server can sustain >100 GB/s memory reads per numa node without much trouble. Some newer HBM enabled, like a Xeon Max 9480 can go over 1.6TBs for HBM (up to 64GB) and DDR5 can reach > 300 GB/s. Even saturating all PCIe lanes (196 on a dual socket Xeon 6), you could at most theoretically get ~784GB/s, which coincidentally is the max memory bandwidth of such CPUs (12 Channels x 8,800 MT/s = 105,600 MT/s total bandwidth or roughly ~784GB/s). I mean, solid state IO is getting really close, but it's not so fast on non-sequential access patterns. I agree that many workloads could be shifted to SSDs but it's still quite nuanced.