Overclocking/4 DIMM's woes

[AD-15]

hello,

Recently, I've been having problems with using 4 sticks of RAM and running them at 1066MHz. Here's the thread:

http://forums.hexus.net/hexus-hardwa...m-4-dimms.html

Basically, in that thread I say how I achieve stability with my system, not necessarily by reducing the speed of the RAM, but by reducing the "FSB-DRAM ratio". So, previously, I could use anything up to 1:1.5. This meant to run my RAM at 1066, I had to use an FSB of 355. This was no problem.

However, I started getting advice from users on the corsair forums that I should not mix old versions and new versions of the same RAM (which is what I was doing). So, SCAN kindly swapped out all 4 sticks for 4 sticks of new RAM (all the same revision/version). However, this has made things even worse.

Whereas before I could use a ratio of 1:1.5, this ratio is no longer stable at all. I tried using 1:1.25, and this seemed to work fine. However, I did not try it with a high enough FSB, and so was not running at 1066MHz, I can't remember the exact speed. So, I decided as I'd found a good, stable ratio to use, I could simply start to ramp up the FSB until I hit 1066MHz on the RAM.

So I went ahead and tried. First I set the ratio to 1:1 (to avoid pushing the ram too far accidentally), then I increased the FSB incrementally, and reached an FSB of 426 successfully. All was looking good, so now I just had to set the ratio to 1:1.25. to finally get a RAM speed of 1066. However, as soon as I did this, the system would refuse to boot. I was totally perplexed, as I'd seen before the stability of the system for me would depend on the ratio, not the actual speed. I reset the CMOS, and set the ratio to 1:1 again. Put the FSB back to 426 once more. No problems, booted fine. Put the ratio to 1:1.25, system fails to boot. I tried this over and over, with different settings for the MCH voltage, but to no avail. Whenever I had the ratio at 1:1, all was cool. As soon as I set it to 1:1.25, no good.

By this point I had decided to try "lowering" the ratio another step - to 1:1.2. This would mean I would have to increase the FSB even more. This is where my second problem comes in. I simply can't test this scenario, I can't achieve the required FSB of 444. I know my board can achieve higher, I've seen people get it to over 500MHz. Do I just have to bump up the "CPUGTLREF" voltage?

In short:

-New memory doesn't like original ratio of 1:1.5 for some reason
-New RAM seems to like ratio of 1:1.25 in some cases (low speeds), but not others (high speeds)
-Can't get FSB past 444


I know I've waffled loads, but I'd be massively appreciative if someone could help!

[CooperXS]

From what I heard from OCZ techy OCing 4 memory sticks may require tweaking of DRAM skew and bumping the tRFC timing. You may also need to bump NB voltage since it helps memory controller. DOn't forget to control thermals.
Although Core uarch is not that memory BW dependant. I'd suggest setting highest stable FSB clocks with 1:1 ratio and try decreasing timings.