Asus M2N-SLI F2-6400 Upgrading to 8GB

[tboyer]

Running:

Asus M2N-SLI (BIOS Rev 1103)
AMD x4 640
Gskill F2-6400CL5D-4GBNT (4GB 2x 2GB Slot 1 & 2)
Radeon HD 4840 x2
Antec Neo 520
Dual Boot 2 Hard Drives: Win7 Pro x64/WinXP SP3 x86

System has been running stable as configured above. I purchased a second matched pair of the same RAM. Machine failed to POST until clearing CMOS. After several tries, it finally booted into XP and appeared stable. Have been able to boot to Win7, but it's very unstable (crashes as soon as any programs are opened). Both sets of RAM run stable when installed separately, but not together. I've set timing manually (5-5-5-15 tRC=21 CR=2T Voltage 1.8). I'm running the same motherboard in another machine with a similar set up and another brand of RAM (8GB 2x 2GB Slot 1, 2, 3, & 4 2 matched pairs) - very stable.

Viewed some similar posts that recommended manually adjusting settings, but would rather not test them out without some advice. Would changing any settings in BIOS help to stabilize, or am I better off exchanging RAM for a mathed set of 4 vice two matched pairs?

Appreciate any help you can offer!

[Tradesman]

What's your tRFC prob want 160 or so, and may want to raise the DRAM voltage .04 and CPU/NB .05 for 4 sticks to see if that helps stabilize things

[tboyer]

Thanks for the quick response! Unless I'm missing a setting in BIOS, this version doesn't have the option of setting to 160 (I'm assuming nanoseconds). It has options 0-4 (clock ticks I assume). Also not seeing any settings that equate to .04 .05.

[Tradesman]

The setting for DRAM Voltage needs .04 volts added to current setting, need to raise CPU/NB voltage .05 higher, the advanced DRAM timing setting for tRFC should be at 110 to 160, needs to be around 160 or the closest setting to that............or just post your BIOS settings and can tell exactly what to change, they may be terming things slightly differently

[tboyer]

Settings available in BIOS:

DDR2 Voltage options available:
1.80
1.85
1.90
1.95
Set to 1.85

CPU Voltage options available (.025 increments) for example:
1.350
1.325
1.300
1.275
Large range of options higher and lower; Auto appears to be about 1.29.
Set to 1.350

All DRAM Configuration settings except as noted below were set to Auto:
Memory Clock Freq = DDR2 800
TLC=5
TRCD=5
TRP=5
TRAS=15
TRC=24
1T/2T Memory Timing=2T
TRFC ? The only options available with the results at each setting:
Auto ? Win7 restarts before booting
0 ? No POST (reset w/ jumper)
1 ? Win 7 restarts before booting
2 ? Win 7 restarts before booting
3 ? Win 7 restarts before booting
4 ? Win 7 restarts before booting
Tried Win XP with one of the settings (1 I believe) ? booted and appeared stable (x86 version)

I?m not sure that this BIOS has the options needed to set the tRFC where it needs to be. The other board I have running 8GB DDR2 6400 of another brand of RAM is set to defaults and BIOS has never been updated (running an older x2 CPU). Wonder if the newer BIOS has some issues? I may try this RAM in that machine if I have time. Let me know if there?s something else I can change here that might make a difference.

[Tradesman]

Is there a setting for NB voltage or CPU/NB? Could try RAM at 1.9...It may be possible that the two sets just don't want to play nice together...Maybe GSkill has some experience with your mobo, they should be in later today

[tboyer]

Thanks. I tried 1.9 when I was testing other settings - same results, and I'm not seeing a setting for NB. Like you said, maybe someone at Gskill has had some experience with this MB. Starting to get a little nervous about resetting via jumper (my case is a tight fit for this setup - have to disconnect fans and pull video card to get at jumper). Sooner or later I'm going to break something and my problem will be sovled with a new MB.

TB

[GSKILL TECH]

Post some pictures of BIOS and we can see if anything needs adjustments.

When did you purchase the two kits? Did you purchase them together? It is possible that the two kits are incompatible.

Thank you
GSKILL TECH

[tboyer]

The first matched pair was purchased 12/22/10 and the second 1/21/11 ? same vendor and part number.

Apologize for the photos, but they should give you the information you need.

[Tradesman]

Think you may have forgotten to add a link to your pics - unless you emailed them direct to GSkill

[tboyer]

Okay - let me try this again...

BIOS Photos:

[Tradesman]

On your second photo the the trfc (towards bottom) just above the 1T/2T Memory Timing setting (which is your Command Rate) shows at auto, might want to look at it and see what it's at or manually set it. Also, if you enable the Overclocking options in the first photo you can prob find the system voltages we talked about

[tboyer]

Settings in the photos are where the board runs stable with 4GB. It also runs stable with XP x86 with 8GB (which obviously isn?t using the additional RAM), but not Win7 x64.

Photo 1 at ?Manual? setting gives you the most options ? that?s it? Overclock (they call it ?AI Overclock?) merely allows you to adjust CPU frequency by predetermined percent increments with that being the only option (literally). Other than that, there?s Auto and Standard (Standard has the same options as Auto ? none).

In photo 2 I?ve tried all of the settings under trfc (0 thru 4). With the exception of 0 (which doesn?t POST), it appears to behave the same (boots to XP, but restarts before getting to Win7 ? will sometimes lock up at splash screen or even get to desktop, but lock up immediately).

Appreciate your help and patience.

[GSKILL TECH]

Send them in for replacements and they should work better.

Thank you
GSKILL TECH

[tboyer]

I really appreciate the excellent support, but I've done some additional troubleshooting today with the following results:

I have another machine running the same mainboard with an older processor (dual core Athlon) and older BIOS version, with 8GB RAM (another brand) Win7 Pro x64. Had a slow day where I could take it off-line and try the Gskill memory in it. It booted the first time and has been running very stable all day with system defaults (everything Auto).

I installed the other 2GB x 4 (matched pairs in the machine that's having problems) with exactly the same results - will not boot to Win7 with 8GB (runs stable with 4GB).

So, I really believe this is probably an incompatibility issue with the CPU/BIOS/Mainboard, or something else in the system, but not the RAM.

Exchanging the RAM probably won't change anything, so my next stop is ASUS support to see if they have any solutions. In the mean time I'll run 4GB and maybe look for a deal on a mainboard with a great track record. I'll add to this post if I ever find a solution.

Thanks again for all your help - you guys are awesome.