Overclocking FSB & Memory Frequency?

[Adamski2000]

Hi all,

Ive just tried to do an overclock of my Intel Core 2 Duo E6400. At the moment I've managed to get it up to 2600Mhz (from 2.13Ghz) by changing the bus speed up to 325Mhz with a multiplier of 8.

One thing I have noticed is that my memory only appears to be running at 325Mhz and latency of 5-6-6-18. I have 4x512MB sticks of Corsair XMS2 PC5400. I have set the DRAM frequency setting to automatic, but the BIOS seems to report it as PC4300 memory when I boot up.

I'm running on an Asus Commando motherboard (Intel P965 chipset).

Any ideas what I can do to up my memory speed? Obviously I can change the memory frequency in the BIOS, but I'm not sure what it should be running at - I think I tried a setting something like "DDR2-600Mhz" or something, but that made no difference.

I've attached screenshots CPU-Z.

Any help would be much appreciated,

Thanks

Adam

EDIT I've managed to change the memory timings to 4-4-4-12 now which is good, but I can't seem to get the frequency any higher. If I do set it to the "DDR2-650Mhz" option in the BIOS it fails to boot (this was before I even changed he timings).

Edited November 11, 2007 by Adamski2000

[Budious]

The memory frequency is measured by multiplying it by a factor of 2 (double data rate). In your CPU-Z screenshot, 325.1x2 = 650.2 MHz effective data rate, close to your 667MHz rated memory.

[Adamski2000]

  Budious said:

The memory frequency is measured by multiplying it by a factor of 2 (double data rate). In your CPU-Z screenshot, 325.1x2 = 650.2 MHz effective data rate, close to your 667MHz rated memory.

Thanks, so it's almost running at full speed, so if I up the bus speed a little more I should be able to get over 667?

[Budious]

Correct, move the bus up to 333*2=667

[Adamski2000]

  Budious said:

Correct, move the bus up to 333*2=667

Seems to have booted ok at 340Mhz - 2723Mhz CPU Speed.

How come the memory ratio (FSB:DRAM) only says 1:1 and not 1:2?

[Budious]

333FSB/333MEM, Intel quad pumps FSB to achieve actual bus speed, and MEM actually transmits two times per hz so it really is 333MEM but effectively 667 in terms on data throughput. Using 1:2 ratio would create a 1333BUS/1333MEM synchronization at 333FSB if you follow me.

[Adamski2000]

  Budious said:

333FSB/333MEM, Intel quad pumps FSB to achieve actual bus speed, and MEM actually transmits two times per hz so it really is 333MEM but effectively 667 in terms on data throughput. Using 1:2 ratio would create a 1333BUS/1333MEM synchronization at 333FSB if you follow me.

Excellent. Thanks.

It BSOD'd at 2700Mhz, so I've turned the FSB down to 330Mhz and it seems ok for the moment.

One thing I don't know is what temperature reading I should be looking at? I'm using SpeedFan and it is giving me several readings for the CPU temperature. See the screenshot:

I guess 73C is too hot?

[Budious]

Download the most recent beta of core temp, 0.95.4 or there may a newer version out, I haven't checked in the past week. It is the most accurate program for reading temperatures. Speedfan has poor calibration and does account for the tJunction value of the processor (the base value it measures from) and the temperatures are misleading, especially for quad cores; it may be more accurate for dual core but I'm not positive on that. Use core temp in any case.

http://www.thecoolest.zerobrains.com/CoreTemp/

I suggest you run memtest or microsoft memory diagnostic from bootable floppy/cd to test memory and timings before attempting to boot Windows as you may corrupt your partition. Make sure you do not have 1T Command Rate set, 2T is best for compatibility and mandatory for 4 modules.

[Lant]

If you can (and if your memory/mobo supports it) you should try to tighten your timings to 5-5-5-15.

[Adamski2000]

Thanks all. I'll give those a try and see how i get along.