IC7 3:2 Mem Divider

Well I'm one of those people that just can't seem to run stable above 275 FSB atm... I couldn't seem to get the 3:2 mem divider to do anythnig what so ever... So I tryed the 3:2 at 275 and I found that it changed my Ram timings... I was running SPD which is CAS 2-3-3-7... Still on SPD but with the 3:2 mem divider CPU-Z showed me running CAS 2-2-2-6.... I was in shock... So I go into my BIOS and manually put my RAM to 2-3-3-7 and sure enough I'm able to get into windows all the way up to 295 FSB... I was running my Ram at 2.8v which might have been to much for the speed it was running so I'm going to take it down to 2.7 or 2.65v tonight and try again and see what I can get...

I thought it might be good to share this little 3:2 mem divider quirk with everyone as I've never seen mention of it in all the IC7 threads I've seen...

Hmmm, I was having the same exact problem trying to get above 275 FSB with my 2.4C and my 3:2 ratio didn't act like it was working except on mild overclocks. Now I can't remember what RAM timings I was using, but I think most of the time I tried the 3:2 ratio, I was just used the SPD setting. I'll have to try this when I get home and see what it does on my mobo.

I tried 1:1 ratio using the SPD setting and my timings were 2.5,4,4,7 in CPU-Z, so next I tried the 3:2 ratio and left it at the SPD setting and now it's 2.5,3,3,6... very strange. I will have to install my 2.4C back in this mobo and play around with the settings more this weekend. This might have something to do with why I though my 3:2 ratio didn't work at high FSB. It might just set the timings too tight. I don't have a clue why the BIOS would be changing the timings like that.

EDIT: I just tried the 5:4 ratio using the SPD setting and I got this RAM timing: 2.5,3,3,7... so it looks like the BIOS auto sets the SPD timings to more aggressive setting at 3:2, slightly relaxed at 5:4, and even more relaxed at 1:1.

1:1/SPD = 2.5,4,4,7
5:4/SPD = 2.5,3,3,7
3:2/SPD = 2.5,3,3,6

Nice info guys .... thx

I think I'll do some checking on this myself and see what happens.


stereo555

With the 1.3 bios the memory timings are also changed in spd or manual mode when you enable the performance settings.

Thanks for going that extra mile Batboy... I just wanted to let others know what Happened to me... I'm glad it's not just me with this 3:2 mem problem...

Also one strange thing I'm becomeing anoyed with... I can run my Ram at DDR 440 at 2-3-3-6 w/ the 5:4 mem divider... When I go to the 3:2 mem divider and manually set my Ram to 2-3-3-7 I get memory errors when I go above 287 FSB... i can get into Windows up to 295 FSB but I either get a Reboot when I run an app or I get the BSOD.... My Cosair PC3500C2 isn't even running at DDR 400 and it's crapping out... I have the Ram Set to 2.8v and I've even tried takeing it down when no luck....

Can anyone shed some light on why this might be...??? I was thinking that maybe it's the N/B HSF.... Has anyone seen the new NB Cooling solution that ABit is going to with the IC7.... It's sooo much nicer than what we are currently getting stock on our current boards....