When is a divider not a divider?

charltonfan1 · 22 Jan 2006 at 16:45

Running 200/150 divider which should give me 206Mhz for my memory. Why is it running 10Mhz less?

Setup:
Opteron 275x10
MSI K8N Neo 4 Sli Platinum w/ Beta BIOS that allows 150 divider
2x1GB PC3500 Gigaram

I think it may be the BIOS isnt set quite correctly perhaps?

marc2003 · 23 Jan 2006 at 00:00

your ram speed has to run at an exact divider of your cpu speed. so numbers have to be rounded up/down a little to compensate. cpuz is showing you what you need to know....

cpu/14 = 2750/14= 196

charltonfan1 · 23 Jan 2006 at 00:08

ahh awesome cheers

Managed to get it working with a 200/166 divider at slacker timings now

Street · 23 Jan 2006 at 01:29

I had exactly the same query last week and someone pointed me in the direction of this helpful little program...

Memfreq

Jimbo Mahoney · 23 Jan 2006 at 08:12

charltonfan1 said:
ahh awesome cheers

Managed to get it working with a 200/166 divider at slacker timings now

That will probably be worse for games and 3DMark.

charltonfan1 · 23 Jan 2006 at 10:21

Jimbo Mahoney said:
That will probably be worse for games and 3DMark.

Really?

So 275x10 Mem @ 196Mhz 3-3-3-7 is faster than
270x10 Mem @ 225 3-4-4-8 ?

charltonfan1 · 23 Jan 2006 at 10:34

Preliminary test:
275x10 Mem @ 196Mhz 3-3-3-7 is just faster in SuperPi 1M out of the two options

Jimbo Mahoney · 23 Jan 2006 at 11:15

... and SuperPi is going to show the most benefit from memory speed / timings.

3DMark 2001 is pretty good for overall system performance.

You'll notice I'm running pretty 'slow' memory speed @ 213 Mhz, but the tight timings and high CPU clock MORE than make up for it.

In fact, if you want to see how heavily CPU-dependent programs are on the AMD64 platform, play around with the settings, keeping everything constant except for memory speed and vice versa with CPU speed.

I found I had to take a huge hike in memory speed to make up for the tiniest drop in CPU speed.

Street · 23 Jan 2006 at 11:41

yeh i found it was best to keep my ram at tighter timings and run a divider... im running a 9/10 divider (180) and my ram is at 211MHz@2-3-2-6

Works better than dropping the timings down to get faster ram.

man_from_uncle · 23 Jan 2006 at 12:06

I am surprise you are not getting more out of your ram there Street. It's default speed is 218mhz at 2-3-2-6 and I've got it running at 236 with those timings, all be it at 3 volts (i'll be checking tonight if it'll do that speed at 2.9 and 2.8).

Jimbo Mahoney · 23 Jan 2006 at 15:21

His CPU is clocked quite high - maybe the mem controller is wimping out?

If so, he's doing the right thing keeping the CPU clock high and the memory clock low (same with my CPU - see sig).

Street · 23 Jan 2006 at 16:33

Ive been playing about with the RAM, seems to top out at about 230MHz@2-3-2-6.

I am only running it at 2.7V though, was under the impression TCCD worked better with lower volts?

Im running my CPU at 267MHz on the FSB and the divider is at 166 now, so its running at 215MHz, if i drop the divider down to 180, then the RAM is doing 233 which it doesnt like at 2.7V. Ill try it later on at 3V with the 180 divider, see if it works

man_from_uncle · 24 Jan 2006 at 11:34

Well, i've tried lowering from 3v to 2.8v and so far it's not made any difference one way or the other. I am of course sticking with the lower, but i'll keep you posted if i make any breakthroughs.