CPU/RAM divider help please

[jrstevan]

I have PC3200 Corsair ValueRam but I set the Memclock Freq to 100mhz to get my top OC speed. My CPU freq is 300mhz with a 8x multi = 2400mhz. CPU voltage is 1.55v. According to the CPU-Z program, my memory is running at 150mhz with these settings. I don't see why. It seems it should be at 200mhz since it is DDR and it is set at 100mhz in the BIOS. When I try to set the Memclock freq in BIOS from 100mhz to 133mhz I get all kinds of errors when I boot so I know it's not stable. The current configuration is stable since I tested with SuperPI and Prime95 for 10 hours with no errors.
I am new to this if you can't already tell, but any feedback would be greatly appreciated. I know I have to get my memory up to full speed or else the CPU overclock will be worthless! For all who chose to help, thank you for your time.

I'm also using a Biostar T6100 754 mobo

 

[F1shF4t]

the diVider is 2:1 (200:100) so for every 2 HTT bus frequency gain u will gain 1 mhz on the memory.

 

[jrstevan]

So, since I increased my HTT by 100mhz, it increased my RAM by 50mhz? If that is so, if I set my Memclock to 133mhz it should end up at 183mhz right? It is PC3200, so anything under 200mhz should work fine but it doesn't. The computer barely boots with anything other than 100mhz Memclock right now.

 

[abs0lut3]

Originally posted by: jrstevan
So, since I increased my HTT by 100mhz, it increased my RAM by 50mhz? If that is so, if I set my Memclock to 133mhz it should end up at 183mhz right? It is PC3200, so anything under 200mhz should work fine but it doesn't. The computer barely boots with anything other than 100mhz Memclock right now.

Yep...you got it right. Try loosen up the timings to see if you are able to get 133Mhz or 166Mhz and work your way up again.

 

[jrstevan]

Ok, I've been reading for hours on the whole RAM timing thing so I hope I got it right. I will post my results.

 

[jrstevan]

Ok, after switching my Memclock to 133mhz and various different timings, I am unable to find any settings that don't make Memtest86 completely puke after the 5th test. I changed the "1T/2T Mem Timing" to 1T and that works fine. What can I do to get my memory up to where it should be at 200mhz?

 

[imported_SLIM]

The usual first things... make sure you're using the latest bios and drivers. Put your system back to stock cpu settings to test the memory as the only variable. Put your memory and HTT at 200 with 1:1 divider. Set memory voltage to 2.7 or 2.8, relax timings to something like 3-3-3-8 at 2T command rate (how many sticks of ram are you using, btw?). If your memory won't survive memtest at these settings, then you probably will never get it to work with that board. If it does work at those settings, you should be able to use the same timings/voltage to run HTT @ 300 with a 2:3 divider (133mhz memory setting). That should result in htt @ 300 and mem @ 200. If everything still runs right, try tightening up the timings.

Hope that helps a little...

 

[jrstevan]

I have two 512MB sticks of Corsair ValueRam. I do not have the newest BIOS for the Biostar mobo, however. Another big question I forgot to mention, is that I cannot figure out how to run my memory in dual channel mode? According to the Biostar website, the board does support it. Do I have the RAM physically installed wrong or is there a setting in the BIOS I have to change? I will update my BIOS an reltry with those settings and see what happens..

 

[imported_SLIM]

Socket 754 is single channel memory only no matter what cpu you are using. There is a 939 version of your biostar board, but the 754 socket simply doesn't have enough pins to support the needed traces for dual channel ddr.

 

[furballi]

Have a $90 ECS NF3/Sempron 3100 combo from Fry's for $90. Corsair VS DDR400 (2 x 512) running at stock Vdimm, 2.5-3-3-6-1T with 5:6 memory divider (166MHz) and 273MHz FSB speed. Vcore at 1.55VDC.

 

[selfbuilt]

Originally posted by: jrstevan
I have two 512MB sticks of Corsair ValueRam.

Try easing off slightly on the CPU freq, down to 298 or something. I found on my S754 Asus K8N board that my high-end Corsairs don't like running at 200Mhz (or higher) with any divider - they will only do 200+ stably when running 1:1. Likely a board/mem incompatibility, as trying 3 diff BIOSes didn't made a difference.

Also as stated above, try lower timmings for the corsairs (e.g. 3-3-3-8 /2T) and definitely bump up you Vdimm to something like 2.65-2.7. I have 3200LL, so I can run 2-3-2-6 /1T at any setting below 200MHz, but I suspect something like 2.5-3-3-7 /2T is likely the best you'll get. Good luck!