XBX2 and clocking RAM at 1066

[Whiskey Mike]

I have a D975XBX2 MB, and OCZ PC8500 RAM (4 x 1GB, Reaper HPC 5-5-5-15 @2.3V). I want to run my RAM at 1066.

I have looked at the settings in the BIOS a number of times, and tried various settings. None of the settings I have found seem to result in the RAM being clocked at 1066. I have tried all settings (from memory, 266, 333, 400, 533). I note that 533 is half of 1066, and wonder if this is the setting given that it is DDR2 memory.

Is there a setting I need to check? Is there mention of how to set the memory speed on this board; search has not been illuminating, maybe I am looking for the wrong thing.

This is probably something simple, so please pardon me if this is something trivial.

[ctal]

Yes, 533 is what you want, which corresponds to DDR2-1066. The first "D" in "DDR" (double data rate) signifies that the memory uses both the positive-going and negative-going edges of the clock signal it receives. So it is in effect clocked at twice the frequency of the clock. That goes for DDR, DDR2, and DDR3.

An excellent utility that will provide you with information about the speed and timings your memory is running at, as well as cpu parameters and other things, is CPU-Z:

CPUID

Regards,

-- Al

[Whiskey Mike]

Thank you Ctal. Appreciate the time.

[Supa-Fly]

Umm... just something to bear in mind... the XBX2 doesnt support 1066. Max supported is 800. You might be able to get it to 1066 by overclocking you FSB but thats the only way of getting the XBX2 of getting to anywhere near 1066. And you wont want to use the 533 strap all to get it there. You would want to leave the board ramm speed at 800 then push up the FSB to somehere near 333. You might also have to tinker around with you ram voltage, and CPU voltage. So simply put, without overclocking your CPU and Board, you wont get the ram to 1066, max 800 on the XBX2

[Whiskey Mike]

Looks like that is the case. Setting the MB to 800 resulted in Everest Ult. reporting real clock @ 400, effective clock @ 800; setting it to 667 resulted in Everest Ult. reporting real clock @ 333, effective clock @ 667. CPUID reported DRAM frequency of 400 when set to 800 and 333 when set to 667.

Already set DRAM voltage to 2.32V needed for this memory to get to 1066 per OCZ.

Other obvious knob to tweak is the BIOS setting for memory reference frequency. It is now set to default. Options are 333, 266, 200, and 133, in addition to default. If I am reading everything correctly, it looks like the default memory clock MIGHT be 266.

Before I go and change the memory clock from default frequency to 333, anybody here got an input?

My immediate goal is not to overclock the cpu, an E6600, just to clock the DRAM at its rated speed.

[ctal]

I'm an Asus and Gigabyte person, and so I'm not particularly familiar with this board or with Intel's bios terminology, but I'm puzzled by a couple of things.

Yes, it looks like this board is not spec'd to support DDR2-1066, but if that's the case why does it provide a 533 strap? Perhaps it's worth trying it.

Also, I don't understand the references in Mike's last post to "memory reference frequency" (333, 266, 200, 133). Those sound like fsb clock rates, not memory clock rates. If so, yes I would expect 266 to be the default, resulting in a cpu clock rate of 1066 MHz (266 x 4) based on quad pumped terminology, and a cpu internal clock rate of 2.4 gHz (266 x 9), the E6600 having a multiplier of 9.

If I'm understanding that correctly, changing the 266 to 333 would overclock your cpu by a factor of 333/266, and would raise the memory speed correspondingly from whatever it was strapped to (for instance, a memory clock of 400 MHz would result in the memory running at DDR2-1000 instead of DDR2-800). However, I would guess that a 25% cpu overclock would not work with an E6600 on an Intel board (which are not known for their overclockability). On the boards from Asus, Gigabyte, etc., fsb frequency can typically be changed in 1 MHz increments; does this board provide a similar capability? If not, I'm not sure what to suggest.

Regards,
-- Al

Edit: If you decide to try the 533 strap, or the 25% overclock with the 400 strap, be prepared of course to possibly have to clear cmos to return to default bios settings, if the higher settings make your board unable to get back into the bios.