ROG Hero X/8700K/DDR-4000 RAM won't XMP boot

S_D · 19 Oct 2017 at 10:44

Hi there!

Memory is CMK32GX4M2F4000C19 (Corsair Vengeance LPX 4000 C19, 2x16GB). Seems that it's too new to be on the Corsair website

So, after Gibbo sorted out my missing-in-the-post 8700K, I've now built my machine (replacing an old 4790K) and I'm trying to get it setup.

Firstly, with BIOS defaults everything works fine. Memory JEDEC to 2133MHz and it boots

If I set it to XMP it correctly detects 1.35v, 4000MHz, but it just won't boot. Hard shutdown and restart and it starts with failsafe settings. Q Code is 55. Lower it to 3600 and it sometimes boots, sometimes doesn't (as Q code 49 and sometimes 55).

Have reseated the RAM.

According to Thaiphoon Burner these are Samsung B-dies. 19-23-23-45, so I expect more.

All the above is with DRAM manual volts at 1.35, VCCIO at 1.25, SA 1.25 and CPU standby at 1.1. All the rest on auto.

CPU is not-overclocked and MCE is disabled. Just want to get the RAM working to spec before I change anything else. I know it's down to the CPU and the stars have to align, etc etc. I would've thought the above voltages would be enough though.

Thoughts?

Simon

S_D · 19 Oct 2017 at 12:08

Just an update. I updated the BIOS (version on the Asus website says 0505 and 'first release version') Actually that isn't the first version as it ships with a much earlier version.

It now boots and runs at 3600. 4000 still out of reach tho. However, the 3600 boot is automatically at CL15

which is very aggressive and I'm surprised it works at all as that's tighter than 8 Pack's 3600 CL16 kit!

If it runs ok at these speeds I'd be happy to stick at them, but what's best to test the RAM?

Alternatively, how can I get it up to 4000?

8 Pack · 20 Oct 2017 at 22:03

HCI memtest.

4000 is IMC dependent on a 4 dimm board the topology of the board makes it difficult to run high speed mems without strong IMC. Maybe this will improve with Bios revisions.

2 Dimm boards like Apex my 4500 kit runs XMP easy...

S_D · 20 Oct 2017 at 22:08

Cheers 8 Pack! Will test them out with that!

bemaniac · 26 Oct 2017 at 08:52

Hey my apex wont run my 4133mhz kit at XMP when I have the m2 ssd adapter in the third slot.

It might do if I up a certain setting but I'm unsure which one.

8 Pack · 30 Oct 2017 at 22:13

Try not using XMP and inputting the settings manually. Maybe your CPU IMC will not run so high?? What Q Code you stuck on???