o/c problem - PC not posting, possibly RAM related

[F@TMAN]

I got myself some DC RAM (check sig), and with my default FSB being 133mhz, I wanted to push it right up to 200Mhz spec, so I dropped my multi to 10x, set CPU:RAM ratio to 6:6, changed nothing else in BIOS and rebooted, only for my PC to not restart (what would happen is, I'll get the screen "Don't shut down while BIOS is saving your settings", then the screen will go black, they'll be some hdd activity for another 20-30 seconds, and then nothing!).

At first, I thought it was the CPU, so I've tried VCore as high as 1.6v (which, IMO, is pretty high for that low clock setting, which is default frequency of the CPU). I've also switched one of my RAM from DIMM 1 to DIMM 2 (atm running in DIMM 2 and 3, have not moved the stick in DIMM3). I've also had my VDimm up to 2.7v, and relaxed my timings to 2.5-3-3-8 (from stock 2-3-2-6 - yeah, it's CH-5!). I have not applied an L12 mod, but these CPU's are known to get 200+ Mhz so it's unlikely to be the problem.

I do remember having problems when I was using one 512MB of BH-5, I had similar BIOS issues when pushing the FSB above 200Mhz, I evenutally fixed it by setting the CPU:RAM ratio rather than leaving it as "auto", but that hasn't helped in this case. Any suggestions? Thanks in advance

 

[flapperhead]

. do u know for a fact the cpu and mb will run 200mhz fab??if not test the cpu and mb for 200 mhz with an easy memory ratio. it could be one of them. also u might want to test each stick seperately in case 1 is defective

 

[hafaphoto]

Vcore

If I am not mistaken, 1.6V is stock on that board for a 2500 XP, so I am guessing it is the same for yours. If you have decent cooling, I would try VCORE 1.7 or so. HOOT gave me the BIOS settings that got me to 200 FSB no problems, in a post long ago. I am by no means an expert, but have you tried 3-3-3-11 RAM timings? Not sure why, but that has worked well for me.

Good luck!

 

[F@TMAN]

thnx for the suggestion, flapperhead, I certainly will try a ratio to test just the CPU @ 200mhz - I know for a fact that my board can run 200mhz (I had some BH-5 @ 225mhz 1:1 ratio with my old 2500+), but that caused me a few problems because I used to leave the ratio as "auto" (which would lead to a similar problem as to what I'm having now). Setting 6:6 in BIOS allowed me to pass 200mhz...as for the CPU, I'm not certain of what it can do (we all know mobile CPU's are 133mhz by default), although my stepping (0351:MPMW) is known to o/c quite well, but as yet I have not applied an L12 mod...

And hafaphoto, I'm using a XP-M 2600+, which has a default VCore of 1.45v - I have tried every increment up to 1.6v and still had same problems! RAM timings were relaxed to 2.5-3-3-11 from 2-3-2-6 and VDimm to 2.7v.

 

[hafaphoto]

Sorry!!

I either did not see the mobile part in your post, or more than likely, just assumed the voltages were the same! Looks like your problem is waaayy over my head, but good luck!

E

 

[F@TMAN]

I was also thinking of testing my ram with DC disabled, can that be done in BIOS or do I physically have to rearrange my DIMMS into slots 1 and 2?

 

[F@TMAN]

Sorry to dig this one up, but I've been overseas, and I just got around to putting some of these ideas into action...

I placed my 2 DIMMS into SC mode (slots 1 and 2 on my NF7-S), and managed to get her to post @ 200x11, 2-3-2-11, 1.5v vcore and 2.6v vdimm - that's the furthest I got! I benched with memtest86, and got errors on test #5 very late in the loop. This reoccured with vdimm up to 2.9v, and timmings loosened to 2.5-3-3-11.

I'm fresh out of ideas, this ram is PC3200 (CH-5), so in theory I shouldn't have any problems, esp. in SC, I rearranged the DIMMS between the slots to no avail. I'm using a 6:6 CPU:RAM ratio. Any further suggestions?!


*EDIT* When using memtest86, what is it that test #5 is testing exactly, and if errors occur, what are the likely causes? If test #5 is the only test in the loop that produces errors, does this pose a threat to stability at all?!