ASUSTeK Computer Inc.-Forum- 955BE & Mushkin 996601 on M4A79T Deluxe

I'm just posting this as a kind of log as to what I'm doing so that others with similar setups may follow and hopefully not repeat any mistakes that I make. Any useful suggestions are always appreciated. Please bear with me as this is rather lengthy, but hopefully helpful.

I'm running a AMD Phenom II x4 955BE on an ASUS M4A79T Deluxe (BIOS rev. 1103) with 8Gb of Mushkin 996601 for the last 4 weeks and, IMO, I've been running pretty stable at a CPU multiplier of x17.5 (3511MHz) and my RAM at 7-7-6-18-24-2T (CL-tRCD-tRP-tRAS-tRC-CR) voltage 1.86V (2 weeks at this voltage, 1.9V before) and DRAM frequency set at 1600MHz, all other settings are auto.

Now in the last week and a half, I've set my multiplier back at stock (x16) due to heat issues, not that big of a deal atm, I've got some ideas on how to fix that (lapping the Xigmatek HDT-S1283 cooler). Now, today, I'm getting a BSOD every time I boot. I reset the CMOS since I can't even make it past the boot screen of Vista. I ran the MS memory tester from my Vista DVD and behold, I got a hardware error at about 39% on the first pass. So, I went ahead and set my 996601 sets to 1333 timings on the main screen and left everything else in auto (9-9-9-25 or so if I remember correctly, I'll check them again when I get home later). I re-ran the MS memory test and got a clean test after both passes and it seems stable for now.

I'm still new to the OC community, but it seems strange to me that after running stable for 3 weeks (admittedly a hot, IMO, CPU ~42C @ idle per Core Temp) I should suddenly start getting the BSOD less than 5 minutes after startup. I'm tried bumping the voltage to 1.8V, tightening the settings at 1333MHz, and playing with the NB frequency and voltage some per the suggestions that Mushkin Sean has been posting in the Mushkin forums.

The only thing that really bothers me is that my overall CPU temp seems to be ~43-45C @ 26-28C ambient (Core 0-3 seem to avg. ~3C higher). The cooler has already been removed, cleaned, and had AS5 placed on it 1 time since the initial install as I thought that the problem may have been to much or incorrect application of the AS5. I had prime95 running and got a failure after 2.25hrs and the overall CPU temp reached 62C. As stated before, I'm going to lap the heatsink since numerous posts I've found on the internet suggest anywhere from a 6C to 12C drop in temperature. Although I'm tempted to lap the CPU, but I don't want to void the warranty yet, so I think I'll save that as a possibly for next spring.

Right now the NB frequency is set 2400MHz (2408.4MHz according to CPU-Z), 2600MHz = BSOD, and everything else is either in auto or its default. The current timings on at 1337.8MHz (hmm, interesting number) are 6-6-6-18-24-2T per CPU-Z, voltage is currently set at 1.90V. All these timings were set manually in the BIOS, with the exception of the CR. The tRC was originally 34, but I tightened it to 24 to see what would happen, so far so good. All other memory settings are left in Auto. The FSB is still at 200 since I've had a few issues in the past getting a BSOD on anything near 220, I'll play with it some more later.

I ordered a lapping kit from EasyPCKits, I got the whole shebang, ArctiClean with Arctic Silver 5, Coarse Lapping Kit, Premium Lapping kit with glass, and the Final Polish Compound. I'm hoping to shed a minimum of 5C.

Update: I completed the lapping last night (2 hours of work) and I could see my reflection in the now mirror like copper surfaces, especially after using the Final Polish Compound. I must say that I don't think I did that bad of a job considering it was my first time lapping a CPU cooler of any kind. Even though the coarse kit was included in my purchase, it wasn't need it since the surface wasn't that rough to start with.

Anyways, to the point, idle temperatures appear to have gone down from ~42C to around ~36-37C, a 5-6C drop

. Initial startup temperature shows 38C with PCProbe II & Everest and actually dips down to 35C at times after everything has loaded. I'm currently avoiding using Core Temp since the only readout I can get in the current version is the hottest core temperature and not all four or the overall. Now for the Prime95 load information, I ran the torture test for 2 hours and for the first hour it seemed to hold at 53-55C (again a 7-9C drop

) but then things started to warm up from there to 60C :shock:

(still a 2C drop) after 2 hours. After much anger

, checking the fans to see they were running and their speeds, opening the case to verify I had indeed clamped the cooler down properly and centered it on the CPU, I realized that the ambient temperature near my tower had risen :idea:

. Well, duh, hotter air pulled into the tower IS going to make it run hotter overall :oops:

.

Overall, lapping the CPU cooler has accomplished its intended goal of reducing normal load temperatures by at least 5C, now I can start with the overclocking. So far I've got a CPU multiplier of x17.5 giving me a CPU OC of just over 300MHz for a frequency of 3511MHz. Naturally temperatures have risen, but I'm not as close to the 62C mark as before. Stability has me a little concerned since I had a total computer lockup in the middle of a game and Core Temp showed the hottest core at 55C (here I'll use it just to get an idea). The next step, I suppose, would be bumping the CPU voltage up from the default 1.350V and see if this minor stability issue goes away. While I'd like to see a 20% OC, I think a 10-12% OC is more realistic with air cooling* given how well my AMD Dragon system heats the air where it's located.

As I have mentioned before, I will continue to keep this updated as I change things with my system. It may be a couple of weeks at times as I experiment to see the stability before I post. If anybody has good ideas or suggestions on setpoints with this particular configuration (ASUS M4A79T Deluxe, AMD Phenom II x4 955 Black Edition, and Mushkin PC3-12800 (996601)) please leave a post and let me know. It may take a couple of days to respond, but I'll at least PM you and let you know I read your post, then I'll post the results later.

*Just so that you all know, air cooling/circulation is currently provided by the stock Cooler Master fans (intake) that came with the CoolerMaster RC-690-KKN1-GP tower (1 120x120x25mm TLF-S12-EB & 2 120x120x25mm R4-S2S-12AK-GP), 2 SilenX 120x120x38mm IXP-76-18 (exhaust), 1 SilenX 80x80x15mm IXP-52-11 (intake blowing the back of the motherboard), and the stock Xigmatek 120x120x25mm CPU fan.