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Another DRAM <-> FSB question

  • CPUs
  • DRAM
  • Product
Last response: in CPUs
September 29, 2008 10:58:43 PM

Hi guys...

I'm trying to get my ram to the advertised 1066mhz

CORSAIR DOMINATOR 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500) Dual Channel Kit Desktop Memory

Asus P5Q Pro + intel e8400

I can only get the FSB to 490 and pass memtest+

Voltage is set to 2.1 as advertised. (I ran it at 2.11 to 2.2 and no go)

DRAM Freq in bios is set to 981mhz.

I've been reading reviews on newegg and they say they can get to that speed without a problem with this ram.

Note: multiplier is 6.5 x 490. Cpuz shows 6 x 490 because of C1E halt state.

I can set it to 8.5 x 400 fsb and the BIOS let's me choose varios DRAM freq speeds and 1066 is one of them. But my

fsb is still 400.

So my questions are:

1- I'm I doing something wrong?
2- Should I leave my settings at 6.5 x 490? would there be much of a performance difference to 533?
3- Is 6 x 490 better (almost stock speed) than 9 x 333?
4- is my ram still running at 533 (dual channel) if I set it to 1066 in bios even though my fsb is 400?

What would be the optimum combination for you guys?

Sorry for so many questions guys.. but the dram:fsb ratio thing is hard...


More about : dram fsb question

September 29, 2008 11:24:17 PM

Just ran a couple of benchmarks..

1:1 490:490

3:4 400:533

What should I go with?
September 30, 2008 1:23:45 AM

Hmm...I seem to remember already answering this... ;) 
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September 30, 2008 1:29:02 AM

I was going to say you cant set your RAM to 1066mhz because you still have the CPU:D RAM at 1:1... but seems you have worked that out for yourself.

Personally i would keep the ratio at 1:1, find then highest FSB you can run (seems like your happy with 490) and then you can try and lower the CAS timing on the Corsair as you should have a little bit of room because its speced at 1066 CAS5
September 30, 2008 6:45:07 AM

a c 127 à CPUs
September 30, 2008 1:07:22 PM

It looks like at 1:1 you are getting about 25% better memory write speeds and about 15% better copy speeds. I say go with the 1:1 ratio.
a b à CPUs
September 30, 2008 4:27:06 PM

To get to 1066 you'll need a different fsb speed and DRAM ratio.
a b à CPUs
September 30, 2008 4:45:27 PM

Try bumping up the Northbridge voltage. When you run the CPU and RAM at high speeds it makes the northbridge work harder.