r1chard_77 :
I have now confirmed that the problem was with compatibility.
It appears that the Corsair 4GB Vengeance 1.35v v8.16 sticks are not compatible with this setup when used in pairs, and alternative Corsair Vengeance 1.5v RAM works fine.
Thanks for the help and advice. For reference my full setup was detailed on the Intel site: http://communities.intel.com/thread/30930
Your making your own conclusions, statements and arguments. IF you take a 'SINGLE 1x_GB stick' and either Enable XMP or use the Rated specs as a pseudo kit i.e. 2, 3, 4 etc of the 'SINGLE 1x_GB stick' then DUH there's NO Rating i.e. NO Guarantee that (together) they will yield Rated 'SINGLE 1x_GB stick' performance. Simple raise the CAS Timings e.g. 8-8-8-24 -> 9-9-9-27.
There are hundreds of posts just from me not to mention the 100's of thousands from other stating
DO NOT MIX-MATCH RAM, Kit(s) 'plural' or worst individual sticks together. And if you do then don't be surprised with failures.
What part of that is unclear to you?!
CPU: i7-3770
MOBO: ASRock Z77 Pro3
RAM: So lets GUESS the CML8GX3M2A1600C9W
1. Update the BIOS to version 1.50 via Instant Flash ->
http://www.asrock.com/feature/InstantFlash/index.asp ; never via OS!
2. DIMM Slots ; CPU: | DDR3_A1 | Empty | DDR3_B1 | Empty |
3. BIOS
Press F9 ; Load optimal default
OC Tweaker:
DRAM Timing Configuration
Load XMP Setting -> Profile 1
VCCSA Voltage -> 1.20v ; the XMP should load 1.20v but if it doesn't then manually change to 1.20v
Press F10 ; Save & Exit = Yes
IF you are still having problems then and the RAM works @ 1.50v then report the issue to ASRock; it's the MOBO's BIOS and not the 1.35v kit.
Mine at this moment i7-3930K with 2 sets of CMZ16GX3M4X1600C9G using XMP @ 1.35 8x4GB: