Here are some suggestions for pushing past the RAM speed ceiling on Haswell-E/X99 systems.
Here are some suggestions for pushing past the RAM speed ceiling on Haswell-E/X99 systems.
X99 and Haswell-E have known RAM compatibility challenges at speeds between 2800-3000/3200MHz. Broadwell-E addressed this by enhancing the CPU IMC significantly. Nonetheless, I'm running on Haswell-E with a 1DPC RAM configuration, which is generally better suited for this chipset. The RAM modules are dual rank, which doesn't align well with this architecture.
I've been able to successfully overclock the memory up to 2666MHz with stable results (quite impressive), but achieving stability at 2800MHz remains elusive. Previously, I could detect a single stick, but newer BIOS versions seem to require all sticks to connect for detection.
I've experimented with various voltages: 1.4V vDIMM with VTTDDR set to auto, VCCSA/SystemAgent at 1.15V, and VCCIO at 1.15V – no success. I've also attempted higher latency settings as a backup, adjusting other primary timings to mimic Corsair XMP profiles from other kits.
Additionally, I've adjusted the tertiary _DR timings, hoping it would ease the load on the IMC, though without any results so far.
System details:
- Motherboard/Chipset/BIOS: Asus X99-A, American Megatrends, version 3402 (avoiding the latest 3505 which caused issues)
- CPU: i7 5820K (Haswell-E)
- RAM: 2x 8GB (16GB) Corsair Vengeance 2400MHz, dual rank, dual channel/1DPC
Ya know...memory kits are binned pretty harshly. There's usually SOME room for overclocking, but you won't always get what you're looking for. I had a 5820k before the 6950X and was running the TridentZ 3200 14 14 14 34 sticks with it at the rated speed just fine. Ran them at 3400 same timings for benchmarking. You might just be at that point with that memory, that you'll just have to add a ton of volts to get it to run higher.
If you're looking for a daily clock, I probably wouldn't want to go above 1.4v, but I'd try as high as 1.45 (with active air flow) just to see where that next level is at. Could also try to bump the system agent voltage up a tad more. I always ended up using a .125v offset....might help.
X99 and Haswell-E are recognized for RAM compatibility problems at speeds between 2800-3000/3200MHz, while Broadwell-E saw improvements by enhancing the CPU IMC.
Currently using Haswell-E, my RAM setup is a 1DPC configuration, which is ideal for this chipset but the dual-rank sticks don’t fit well with this architecture.
I’ve been able to overclock the memory up to 2666MHz with stable results (quite good), though I haven’t managed to get it to run at 2800MHz consistently. Previously, it would work with just one stick detected, but newer BIOS versions seem to require all sticks to connect.
I’ve adjusted voltages such as 1.4V vDIMM with VTTDDR set to auto, VCCSA/SystemAgent at 1.15V, and VCCIO at 1.15V – no success.
I also experimented with generous latency settings, up to CL18, using modified primary timings that mimic Corsair XMP profiles from other kits.
Additionally, I’ve tried adjusting the tertiary _DR timings (found in BIOS) to ease stress on the IMC, though without any results.
System details:
- Motherboard/Chipset/BIOS: Asus X99-A, American Megatrends, version 3402 (avoiding 3505 which caused issues)
- CPU: i7 5820k (Haswell-E)
- RAM: 2x 8GB (=16GB) Corsair Vengeance 2400MHz 14-16-16-31, dual rank, dual channel/1DPC
It seems the right forum for this topic is OCN – there you’ll find more informed responses.
http://www.overclock.net/f/
Ya know...memory kits are binned pretty harshly. There's usually SOME room for overclocking, but you won't always get what you're looking for. I had a 5820k before the 6950X and was running the TridentZ 3200 14 14 14 34 sticks with it at the rated speed just fine. Ran them at 3400 same timings for benchmarking. You might just be at that point with that memory, that you'll just have to add a ton of volts to get it to run higher.
If you're looking for a daily clock, I probably wouldn't want to go above 1.4v, but I'd try as high as 1.45 (with active air flow) just to see where that next level is at. Could also try to bump the system agent voltage up a tad more. I always ended up using a .125v offset....might help.