FSB and RAM

[mnelson07]

Currently, my OC is stable at 3.4GHz v1.38 and my RAM timings are 4-4-4-12. However, I was noticing in BIOS that under the RAM's frequency said 800 (above the manual clock speed on the P35-DS3R), but then to the right I saw 756 which is double my FSB of 378.

Is it optimal for my FSB to match that 800 MHz that the RAM runs at? I guess honestly I'm not understanding the relationship between the RAM and CPU, and the things that come along with them like the CPU's FSB and the RAM's MHz.

Also, CPU-Z shows under the Memory tab the frequency is 378 MHz like my FSB. It's a 1:1 ratio as well.

I guess I just want some clarity.

[veedubfreak]

You might try setting the memory multi to 2.5 or 3.0 and see if you can stay stable. Some people say that running 1:1 is best but it doesnt really matter if you have good memory that can overclock well.

[b1gapl]

I think it's good to keep a 1:1 ratio, so that neither the RAM or CPU, is holding each other back, when one is faster or slower than the other.

[mnelson07]

Is CPU-Z reading it as 1:1 even though it actually isn't since its 756:800 but it's just close enough to round to 1:1?

I was thinking about pushing 3.6Ghz anyhow which will obviously push my FSB to 400. But I'm worried it might run too hot. I think with what I'm running now I'm idle at 30-35 and on load im in the mid to high 40's according to Core Temperature.

[b1gapl]

Those are excellent temperatures. You can definitely reach 3.6GHz.

The 800 756, you are seeing in the BIOS, is not the ratio. The 800 is the RAM's default speed, and the 756 is the speed that your RAM is running at, now.

[mnelson07]

Essential, double the FSB and that's your RAM speed? So then the CPU is bottlenecking the RAM? I know RAM can get to 800/1000/1200 MHz.

Ok, here is what I'm thinking in my head. Not necessarily to do, just to make sure I'm clear.

Let's say I want 3.6GHz. Staying with a multiplier of 9, I'd have to make the FSB 400 which will make my RAM's speed 800.

Now if I wanted to get 1200MHz on my RAM, I'd just drop the multiplier to 6 and set the FSB to 600.

So on and so forth 1000MHz RAM means multi = 7.2; FSB = 500.

Correct?

[b1gapl]

lol...Ok, that might be taking it a little too far, with the 600FSB. As I think it's only possible with watercooling, or phase change.

500FSB is a bit much, unless you drop the multiplier.

When it starts to get that high, RAM is easier to get to that level. Where as the FSB is limited. So it's alright if the RAM is running 100MHz faster, than the FSB. So like 400FSB and 500 for RAM. Or, if you can reach 500FSB, then 600 for RAM.

[mnelson07]

It was all hypothetical, just to make sure the numbers are right as all of the ratios/formulas are correct, not whether or not they are feasible.

[TheOtis]

Originally Posted by mnelson07

Is CPU-Z reading it as 1:1 even though it actually isn't since its 756:800 but it's just close enough to round to 1:1?

I was thinking about pushing 3.6Ghz anyhow which will obviously push my FSB to 400. But I'm worried it might run too hot. I think with what I'm running now I'm idle at 30-35 and on load im in the mid to high 40's according to Core Temperature.

3.6 on air? I'm surprised you're getting those temps on that quad with air cooling.

You might want to try another temp program. CoreTemp is known to be the most reliable, but mid to high 40's under load on an overclocked Q6600 is fantastic, watercooling fantastic. Sounds a bit too good to be true.


Do you have a G0 or B3? Even if you have G0, mid to high 40's on an OC'ed quad is lowwwwwwwwww.

[mnelson07]

Originally Posted by TheOtis

3.6 on air? I'm surprised you're getting those temps on that quad with air cooling.

You might want to try another temp program. CoreTemp is known to be the most reliable, but mid to high 40's under load on an overclocked Q6600 is fantastic, watercooling fantastic. Sounds a bit too good to be true.


Do you have a G0 or B3? Even if you have G0, mid to high 40's on an OC'ed quad is lowwwwwwwwww.

Those temps are for 3.4 on air. Not a big difference, just pointing it out.
What other program would you recommend? SpeedFan seems much more inaccurate than Core Temp. But I'll D/L it and run it with Core Temp to see the difference on their readings when I try for 3.6GHz.