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

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

#21

Post by gruez »

speeder wrote: post #8
morceauxdebois wrote: post #2

I'm happy that I put off upgrading my pc long enough to skip a RAM generation.

I have a 4690K and my RAM is a 32GB EVGA DDR3 ram that I suspect was made by hynix or the other manufacturer of fast rams, that runs at speed up to par with the slowest DDR4 but with DDR3 latency, it is very awesome. I wonder if DDR5 will be fast enough to compensate for the slower latency (or maybe they improved latency this time?) To be honest I didn't felt yet any need to move off my current machine, I would only…

>that runs at speed up to par with the slowest DDR4 but with DDR3 latency, it is very awesome.

AFAIK ddr4 having higher latency than ddr3 is a myth. It has a higher cl number, but that's measured in cycles, so the higher cl number of ddr4 is compensated by its higher clocks. The actual latency (measured in nanoseconds) is about the same, or slightly lower in ddr4 than ddr3.

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

#23

Post by josmala »

morceauxdebois wrote: post #2

I'm happy that I put off upgrading my pc long enough to skip a RAM generation.

I was planning on same thing, until I estimated how much faster modern PC was at single threaded compilation tasks compared to my old one, and how it impacted my productivity. I should of upgraded earlier.

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

#24

Post by pedrocr »

nullifidian wrote: post #5
satisfaction wrote: post #4

Earlier quoted context omitted.

Same here, I'm running an FX-8370 and DDR3 now, going to build a Threadripper + DDR5 late next year, hopefully.

You are very patient. I'm not sure about skipping this generation, because who knows when we will get ECC UDIMMs for AMD cpus. It could be late 22 or or even mid 23.

ECC on AMD seems quite hard in practice even though the CPU support isn't artificially limited like with Intel. Making sure the motherboard supports it is hard and then the RAM options are extremely limited and generally quite slow and expensive. Threadripper is maybe better but that's quite a jump in cost. It would be so nice to finally be able to assemble low-cost home servers and workstations with ECC but it remains a niche where you have to give up a lot to get it.

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

#25

Post by gruez »

Macha wrote: post #15
nullifidian wrote: post #3

Will we get performance increases, and how big will they be in the average case, not for some specific codes with low cache hit ratio on large datasets, and attributed solely to bandwidth increases and not architecture IPC improvements?

Depends a lot on your CPU's architecture as well as workloads, how far ahead it prefetches vs how often it's stalled on large memory reads. So it's hard to know. e.g. Zen+ (Ryzen 2000) was seeing 10% in some gaming workloads going from DDR4-2400 to DDR4-3600, but it's much less drastic on Intel CPUs or even Zen 2 (Ryzen 3000) because the memory controller is smarter so the slower RAM is less of a detriment. And then…

>even Zen 2 (Ryzen 3000) because the memory controller is smarter so the slower RAM is less of a detriment

Source? I'm not of zen 2 having a "smarter" memory controller that improves performance. AFAIK the only improvements that they did implement (that could be construed as relating to the memory subsystem) was larger caches and a better branch predictor.

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

#27

Post by SketchySeaBeast »

josmala wrote: post #23
morceauxdebois wrote: post #2

I'm happy that I put off upgrading my pc long enough to skip a RAM generation.

I was planning on same thing, until I estimated how much faster modern PC was at single threaded compilation tasks compared to my old one, and how it impacted my productivity. I should of upgraded earlier.

What did you move from and then to? As near as I can tell IPC haven't increased that much in the last little bit. Or was your CPU pretty old?

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

#29

Post by epmaybe »

gruez wrote: post #21
speeder wrote: post #8

Earlier quoted context omitted.

I have a 4690K and my RAM is a 32GB EVGA DDR3 ram that I suspect was made by hynix or the other manufacturer of fast rams, that runs at speed up to par with the slowest DDR4 but with DDR3 latency, it is very awesome. I wonder if DDR5 will be fast enough to compensate for the slower latency (or maybe they improved latency this time?) To be honest I didn't felt yet any need to move off my current machine, I would only…

>that runs at speed up to par with the slowest DDR4 but with DDR3 latency, it is very awesome. AFAIK ddr4 having higher latency than ddr3 is a myth. It has a higher cl number, but that's measured in cycles, so the higher cl number of ddr4 is compensated by its higher clocks. The actual latency (measured in nanoseconds) is about the same, or slightly lower in ddr4 than ddr3.

I think that's what he's saying, that if the latency is equivalent on best ddr3 and lowest ddr4 and ddr3 is cheaper or you already own it maybe better to wait.
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