Increase your multiplier or your FSB

Chronictank · 18 Apr 2006 at 15:29

I am a little confused about this issue now, originally i thought maxing your FSB gave you the highest performance increase, but rescently i read that as a result you also put strain on your RAM so a high FSB and a low multi is a bad thing. But then your cpu runs hotter on a higher multi as i need to pump more volts into the cpu to achieve higher speeds, so surely a higher FSB is better?
I found by increasing the FSB i can can get it to about 320 but i cant take the multiplier off 4.5 without causing instability, i decrease the FSB to 300 and i can get it up to 6x.
But in order to run the multi at 9x (max mobo supports) i need to reduce the HTT to 255ish at 1.475v before i stop increasing due to high temps and losing stability (sythe ninja inc next week so should help on the temp part).

I have a Opteron 165, DFI Lanparty NF4 Ultra-D, G.Skill 2GB DDR HS PC3200 (2x1GB) CAS2.5 Dual Channel Kit and currenlt a Zalman Aero Flower.

Current settings:
Ram: 2.5,3,3,6 - 1t @ 2.7v, divider set to 5/6 in the bios but cpu-z says cpu/11

FSB: 240Mhz
Mulit: x9
Volts: 1.4v

Dutch Guy · 18 Apr 2006 at 15:46

You need to find the limits of the individual components, if your system can run at 320Mhz FSB stable you need to increase the multiplier while keeping the FSB at 320Mhz until it becomes unstable, increse the VCore and try again (all the time keep the FSB at 320Mhz)

Also during testing keep the memory at 1:2 to remove that as a bottleneck.

When you find the max CPU speed (and FSB speed) then change the memory divider to see how fast you can run that.

booyaka · 18 Apr 2006 at 15:47

It usually about finding the best balance between the multi and the FSB.

Normally most people will have the multi set at almost the max for the chip.

ie my max multi for the 3700 is x11 (locked up the way) and therefore my current settings are 245fsb x 11 = 2700mhz.

9x 255 is still a good overclock - that's about 500 MHZ over the rated speed of the chip so i would say that you have reached the limit of your chip about there. Still got to be happy with that!

If you want to go further you may need to slacken the timings of the ram off a bit.

xirokx · 18 Apr 2006 at 16:10

before you overclocked what was your multi set to? Isnt 4.5 a little low? Also have you lowered the HTT?

What was your FSB originally?

It's true you have to taken each component seperately to find its limit otherwise you will be going around in circles..

FSB: 240Mhz
Mulit: x9
Volts: 1.4v

If the above were your original settings then your overclock 320 x 4.5 means your system is running slower...

Have you tried reading the guide in the overclocking thread?

Chronictank · 18 Apr 2006 at 16:30

Apologies for the above it was supposed to be 350 as the max fsb not 320.
i read the newbie oc guide, which says to find the max fsb and increase the multiplier after you have found it.
I can get the fsb to 350 with no problem (multi set to 4x),
but as soon as i put the multi up i start getting problems (prime95 getting errors) then i increased the multi and volts until 1.5x as i dont want to go over that, but still couldnt go above 4.5x without stability/heat issues
So i went the other way round, set the multi to 9x then increased the fsb in 5 mhz increments increasing the cpu voltage every time it became unstable up to 1.5v

I didnt however set the memory to 1:2 i just left it as default, perhaps thats where i went wrong?

Edit: i am up to 2.3Ghz thanks to better ram timings

(fsb 260 multi x9), i think i could go further as the volts are still only at 1.4

ted34 · 18 Apr 2006 at 16:34

A system set at 220 x 10 will be slightly quicker than a system at 200 x 11 (due to the slightly higher fsb) with the ram at the same speed and timings. Your better off leaving your ram at tightest timings possible at speed of 200mhz and then keep it at that by using dividers. Then just up the fsb to raise cpu speed - leave the multi at max. Only time to lower multi is to test board max or memory max and so eliminate the cpu from the bottleneck.

e.g. Say your cpu has max mulit of 11 and its stable up to 230 x 11 (=2530mhz)
If your ram can do 250 at tight timings (say 2,2,2,5, 1t) then run it at that but obviously you cant use 250 x 11 as the cpu isnt stable so use 250 x 10. Ok your losing out on 30mhz but running the ram at 1:1 will compensate for that tiny amount. If the difference was more like a 100mhz then run benchmarks like superpi to see which is quicker

Chronictank · 18 Apr 2006 at 16:37

ah ok, i guess i misunderstood the newbie oc thread.
I thought i was supposed to leave the fsb maxed and bring the multi up. doh!
thanks for all the help

xirokx · 18 Apr 2006 at 16:57

Remember do 1 thing at a time....

So keep the multi to what is was originally...then increase the FSB by 5mhz at a time...When its unstable lower the multi as I imagine increasing it wont work if its unstable when you lower the multi then increase the Dcore as stated in the guide...Now once you have reached your max overclock for multi and fsb then start on your RAM...otherwise you'll only get a headache...

Goodluck