03-15-2016 03:49 PM - edited 03-15-2016 03:50 PM
Just purchased two 12GB triple-channel Tactical DDR3-1600 kits to max out my old P6T SE (CPU is an i7-920). Initial boot showed the RAM running at 1066 (all BIOS settings in AUTO). I manually selected 1600 and was able to successfully boot. CPU-Z shows the timings as:
DRAM Frequency - 803.2 MHz (this bounces around as the system tweaks)
FSB : DRAM - 2:12
CL - 9.0
tRCD - 9
tRP - 9
tRAS - 24
tRFC - 128
CR - 2T
According to SPD the timings should be (XMP-1600) 8-8-8-24-36-2T @ 1.500V
If I attempt to force those timings in the BIOS (default voltage is 1.5 so no need to modify that) I can't post. Am I running into a chipset limitation with all six slots loaded? Anyone have any success in achieving spec'd timings with this configuration? Interesting to note the Qualified Vendors List that ASUS has for this motherboard does not show any configuration that is approved for 24GB of RAM installed. o.O
Any thoughts appreciated.
Solved! Go to Solution.
03-16-2016 05:54 PM - edited 03-16-2016 05:56 PM
Wanted to provide some additional information after a whole lot of reading last night and attempting various configurations as a result.
Looks like I fell for the marketing hype with this ... yes the motherboard can run 24GB of RAM and yes the motherboard can run DDR3-2000 (or DDR3-1600) ... but there is no official support to do both at the same time.
I surfed on over to the ASUS VIP forum and started reading at the very beginning of the P6T SE area. The first post was on March 6 2009 and it didn't take long for the memory complaints to show up. What a debacle. Short version is, it's a total turkey shoot and this motherboard has seen serious memory issues for a lot of users.
My results ... I had the system running stable with the timings mentioned, which didn't match the advertised timings. I enabled XMP in the BIOS using Ai Tweaker and the BIOS recognized the correct timings and (here's the kicker) bumped the QPI voltage from 1.2V default to 1.35V. Now I was able to successfully boot with the advertised timings and a full 24GB of RAM. Then I let the computer idle long enough to put the monitors to sleep ... couldn't wake it up, had to do a hard reset. Windows 7 showed a BSOD message after booting back up. Happened every time I let the monitors go to sleep (the system itself is set to never sleep).
Now I have removed one of the kits and am running a single kit in XMP mode with the correct timings. Can successfully resume from sleeping monitors,
In conclusion, kudos to Crucial for making a stellar product that works as advertised and indeed was running stable even in an officially unsupported configuration. In my situation I am more inclined to use 12GB of RAM at the tighter timings than 24GB at the looser timings. Good to know that Crucial makes it possible to choose between those two options though.
Still interested in anyone else's mileage with similar configurations.
(edited to get rid of the *bleep*s)
03-23-2016 04:18 PM
Futher update (in case anyone cares)
I chatted with Crucial tech support and they recommended that I run MemTest86 with all 24GB installed and running at XMP settings. The test passed, so I have since disabled the monitor sleep function of Windows 7 and have not had an issue. It's a pain to have to manually turn off the monitors when finished using the computer, but it does help narrow down the source of the problem. I am going to try connecting with nVidia support to see if they can help. Also, I do plan to upgrade this computer to Windows 10 in May and I wonder if that might alleviate the problem. Will update this thread if anything else happens.