DDR5 Is Coming: First 64GB DDR5-4800 Modules from SK Hynix

Re:DDR5 Is Coming: First 64GB DDR5-4800 Modules from SK Hynix by gameswithgo on Tuesday October 06, 2020 @10:09AM (#24697781)

The reason Zen1 (and 2) speed up a lot from ram speed increases is because the memory controller speed is tied to ram speed. So when you bump up the ram speed you also bump the memory controller speed, which reduces ram latency and inter-cpu communication latency.

There is no telling what the memory controller -> ram ratio will be with ddr5, the memory controller has speed limits, so you aren't going to get free speed just because the dr5 starts at 4800, because the zen memory controller can't run that fast anyway.

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Re:DDR5 Is Coming: First 64GB DDR5-4800 Modules from SK Hynix by formerly_proven on Tuesday October 06, 2020 @11:27AM (#24698712)

Zen 2 IMC can do DDR4-5000, but it's rather pointless, because it requires un-coupled mode with IFCLK != UCLK (since IFCLK cannot be pushed to more than ~1.9 GHz, and even that is not stable on many CPUs), which adds so much latency that you _need_ DDR4-5000+ to approach the performance of DDR4-3800 with IFCLK = UCLK.

[ Parent | on HN ]