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*Official* Intel DDR5 OC and 24/7 daily Memory Stability Thread

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Let it begin, boys...

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There's this guide: MemTestHelper/DDR4 OC Guide.md at oc-guide · integralfx/MemTestHelper
While it's written for DDR4, and the specific timing recommendations don't really apply, the principle and order of tightening timings remains the same (lower one timing at a time, test stability, rinse and repeat)

Here's what's changed in terms of DDR5 OC on Intel CPUs:
  • tCL needs to be a multiple of the gear ratio, in gear 2 that means it has to be an even number, while gear 4 means it needs to be a multiple of 4
  • tRCD and tRP are now separate timings
  • tREFI can now run as high as 262143, this is the only timing where higher = better.
  • Tertiary timings for Intel on DDR5 are now at minimum 7, rather than 4.
  • Due to the increased number of banks on DDR5, _dg timings have a significant impact on performance, _sg timings doesn't make the same kind of difference.
  • tRFCpb / tRFCsb is a new timing, which refreshes a single bank, this allows the CPU to still access memory while data is being refreshed. Tightening it works similarly to tRFC.
  • Some testmem5 presets work better than others, ironically enough I've found 1usmus_v3 to work quite well.
  • tWR is controlled by tWRPRE and tWRPDEN, if you want a formula: tWR = tWRPDEN - (tCWL + 8)
  • tWTR_S and tWTR_L are controlled by tWRRD_dg and tWRRD_sg respectively. tWRRD_dg and _sg can have a significant impact on performance, and they can often only tighten 2-6 ticks from stock timings.

For the Hynix ICs you're using, here are my suggestions as a starting point:
VDD/VDDQ: 1.35V
tCL 11 ns
tRCD 13 ns
tRP 13 ns
tRAS 13 ns
tRFC 130 ns
tRFCpb 90 ns

Note that I listed these values in terms of absolute time, and you'll have to multiply them by the actual frequency to get a suggested timing.

Example: tCL at DDR5-5600
DDR5-5600 has an actual frequency of 2.8 GHz
tCL is suggested 11 ns

tCL in ticks = 11 ns * 2.8 GHz = 30.8
Rounded up to the nearest multiple of 2, we get tCL 32 as a starting point.

For the rest of the timings, we then get
tRCD 37
tRP 37
tRAS 37
tRFC 364
tRFCpb 252

I use GigaHertz here because Giga (10^9) complements nano (10^-9) so that I don't need to multiply or divide by 1000


Hope this is at least somewhat helpful to you.

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:unsure: :sleep:
 

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CL lookin THICC 😘👌
 

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question, why dont they make use of VLP pcb to allow for more heatsink material to stick out?
Crucial's Ballistix Tactical LP is one of such example.
 

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non-rgb looks great for sure. I probably will not be an early adopter but look forward to seeing the results of what people can pull off with them and the progression.
I have the DDR4 version in RGB and they look awful in white led mode.
 
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Discussion Starter · #12 · (Edited)
6400 XMP @ 105k GB/s and 65ns latency already?
 
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6400 XMP @ 105k GB/s and 65ns latency already?
...This is why I appreciate threads such as this one ! While I won't be an early adopter (currently running DDR4 4000 / CL14 -14 -14), I'm hoping to see how progress re. DDR5 speed such as 6400XMP unfolds, along with latency improvements. Here's hoping for DDR5 "B-die like" kits to keep the tradition alive.
 

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A popular online retailer here in Australia has 2 kits of DDR5 listed for sale & they are already sold out, this with no reviews or testing anywhere on the www. Also D5 mobos sold out yet no sign of cpus for them yet!
What was that saying about "fools rush in where angels fear to tread" again?
 
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