Overclocking: FSB vs RAM speeds

[martini161]

first try cpu voltage

[Skippman]

Well, played with it some more tonight. Was able to get it to post with it set to the following

CPUX = 8
FSB = 400
CPUV = 1.45V
NBV = 1.65V

I started to get processor errors every other boot from the bios and Vista flat out refused to start. I'm now running with these settings.

CPUX = 8
FSB = 366
CPUV = 1.35
NBV = Auto

This has resulted in basically the same speed and spec I was getting before I dropped the multiplier but the FSB is increased. I don't know if this yields any performance gains. Temps appear to be the same as this shot shows.



I was previously able to get the machine to post with 366 x 9 at 1.3. I'm going to see if that's stable or not.

[Skippman]

I was able to get it to run stable at 3.2G.

CPUX = 9
FSB = 366
CPUV = 1.35
NBV = Auto

I let Prime95 run for 45 minutes just to be certian. Here's my benchmarks.



Anything I try to get it to run faster than this and things get wonky. I've tried the CPU voltage at 1.45V. I've tried upping the North Bridges voltage but it just won't run stable and I'm concerned about running the CPU at 1.5V or greater. I think I might have reached the peak of my overclocking ability.

[Skippman]

Should I leave the RAM clocked 1:1 at the 366Mhz FSB, or should I set it to 400mhz and adjust the timings?

When I try to set the RAM voltage to 2.1 as the manufacturer says it turns red in the BIOS. Does that mean I'm over-volting the RAM or is that just the BIOS saying that 2.1V is generally outside most RAM modules abilities?

[DMB2000uk]

DDR2 is normally rated at 1.8v, but some faster RAM needs more than standard volts to work properly at their rated speed.
As it's specced by the RAM manufacturer, don't worry about it in the BIOS.

Because of the overclock, Is there a divider that lets you run 400Mhz (800mhz DDR2) RAM at 366FSB?

Dan

[Skippman]

I'm not sure. I wouldn't even know how to calculate that.

[DMB2000uk]

If you go through the options of the speeds in the BIOS it should tell you what the resulting memory speed is before you apply it.

Dan

[martini161]

i would try 400mhz at like 7 multi to see if your motherboard or procesor is limiting you , i have a feeling its the motherboard

[Skippman]

i would try 400mhz at like 7 multi to see if your motherboard or procesor is limiting you , i have a feeling its the motherboard

Oh I'm beginning to agree. But why would I want to run at 2.8G when I'm kicking 3.2G now. Surely there can't be THAT much of an improvement by running the RAM in syncronous. Or are you saying to run it at that to see if it will even run with a 400mhz bus at any multiplier?

[DMB2000uk]

He's saying scale back the CPU so that we know it's not that, then see if the FSB will go any higher. (and if it doesn't, put it back to what it's at now).

Dan

[DaIceMan]

with my E6600 and Asus board, I HAVE to raise the NB Voltage, or the system will not overclock. I can't seem to find my overclocking notes, but I want to say that I had to run the NB at 1.56V to make everything happy at 3.2.

[Skippman]

I tried setting the timings manually last night on the RAM and couldn't get it to post with the factory timings at my rated FSB.

I played STALKER for about an hour this morning and had two lockups.

I'm wondering if I'm undervolting the memory to much as I have it set to auto and the manufacturer states it needs 2.1V. I'm going to try ramping up the voltages tonight. Do you think I should also increase the voltage on the FSB?

[Skippman]

Well, it's offical, I've hit the wall. I was able to get it to post last night at 400mhz x 8 at 1.52V with the north bridge at 1.55V. I'm concerned about volting the north bridge any higher as it's passivly cooled.

Set the RAM to 2.1V per manufacturer spec and the systems stable in STALKER now as well.

Current Setup:

CPU = 366 x 9 = 3.3Ghz
CPUv = 1.35V
NBv = 1.5
RAM = 2.1V

[davidm71]

Skip,

You might want to check this article out. It has detailed the relationship of ram speed to fsb in regards to mb/s performance. Although it is limited to Abit's IN9-32X Max motherboard I found it very interesting.

http://www.xbitlabs.com/articles/mainbo ... max_9.html

That also happens to be the motherboard that I am using right now and I also have an E6600 that I am trying to improve its performance by raising my overclock from 2.7ghz 300mhzx4 fsb. I hit a wall booting without bsod at around 3.15ghz around 1.355 volts. I know I could raise the cpu volts but the label on my e6600 box says 1.35V max. So I would rather play loosely by the rules to overclock my system. Also read a report about my motherboard that said not to go over 1333mhz fsb times 5 percent. Seems like my motherboard has a history of poor overclocks though I'm at 355x4 right now and 1hr and half orthos no problems at 8x multiplier. If I raise the multiplier higher I will have stability problems I am sure of it unless I raise the vcore up to 1.4 but I am not sure if raising the voltage beyond manufacturer recommended voltage is sound. A lot of people do it but I am afraid to tell you the truth.

Here is where I am at right now:

E6600 at 2.84ghz (355x8) 1.355 volts
4x1gb pc-8500 ram 2.25v at 1067 1.4v northbridge (have fan on nb).

Stress testing right now. Interesting to note that on my motherboard according to that article 300mhz fsb yields better system performance than 333 with a sweet spot around 350mhz...

Good luck with your attempt...

Dave.