Instability using 4GB of RAM (4 DIMM's)

[AD-15]

hello,

Some of you may remember the thread I made earlier this week on using 4 DIMM's and getting my system to boot with the RAM set to 1066MHz. Well, I sorted it out by swapping the pairs around, but now I get another problem.

Until now, I've used the system without issue, but using an FSB: DRAM ration of 1:1.5. I was using an FSB of 355MHz, and so had 1066MHz as the clock for the RAM, without issue. However, today, I tried using the bog-standard non-overclocked FSB, and the ratio of 1:2 to get 1066MHz. This gave me a cascade of freezes, reboots, BSOD's etc.

I'm running memtest right now, and a third of the way into the first pass yields no errors. I'll leave it going for a few more hours. I don't think it's the RAM though.

What could the problem be? Does the motherboard not like FSB: DRAM ratios higher than 1:1.5 when using all 4 banks for memory? Could increasing the MCH voltage solve this?


Thanks!

[Will404]

Wats the voltage at now????

[inonefly]

whats ur MCH voltage now? if it's default I'd up it a few notches as you are using 4 sticks

[Tetras]

Could increasing the MCH voltage solve this?

It usually does, yes, try it.

[Agent]

It is required to up the voltage on my QuadGT's Northbridge to get it to boot with 4*! gig

[AD-15]

hello,

The DDR voltage is at 2.1V and the MCH at 1.25V (default).

Forgive me if I sound ignorant, but how would increasing the MCH voltage fix a problem with the divider? Isn't it the FSB voltage that should be increased?

Thanks again for your input guys!

EDIT: Also, by how much should I increase the voltage? Different motherboards use different "notch sizes" don't they?

[Tetras]

The MCH is the northbridge (Memory Controller Hub, which is what controls the FSB too). As to why your rig should be stable with one divider and not with another, I can't answer that question (these things are technical voodoo).

It is almost always required to increase the northbridge to have a stable system when running 4 sticks, due to the increased load on the memory controller. If the change doesn't have the desired effect, then feel free to return to defaults.

[inonefly]

as long as the nb temp is ok you should be fine, try 1.3, 1.35, 1.4 etc...until it's stable, then lower it by the smallest "notch size" available until it's not stable and back to the last stable one

[Agent]

Forgive me if I sound ignorant, but how would increasing the MCH voltage fix a problem with the divider?

Dividers are controlled via the northbridge.

As for how much, just up it a few notches and see if it boots. I'll check what voltage mine needs tomorrow - although I don't need to worry too much as its watercooled

[AD-15]

hello,

Well, I've tried upping the MCH voltage quite a bit but it makes no difference, the system still fails orthos after 16 seconds.

I've tried setting the divider to 1:1.6 instead, and this has solved all the issues. However, it does mean I'm running the memory over 200MHz slower than I'd have liked.

I've had a look at the corsair support forums, and it confirms what I've found. The memory simply cannot be run using the "higher" dividers when 4 banks are populated. It's not much of a problem, as I can overclock the FSB instead.

The only problem that remains is should I set the MCH voltage back to default? It seems to run OK at that voltage, but the only worry I have is that would I be stressing the northbridge if I don't up the voltage a notch from default when all 4 sticks are loaded?

Thanks for all your help guys!

[Agent]

The 'stress' (mathematically speaking) that its under won't change depending on how much voltage is going through it. It will however start to fail if there isn't enough voltage at the stress level its being put under (if that makes sense )

Feel free to knock it down - if you have problems, turn it back up. Nothing to lose really

[AD-15]

hello,

Thanks for the advice mate.

How can I test for which voltage it should be at? Should I just run a bit of Orthos at the default voltage level, and if it works leave it at that?

[inonefly]

as long as ur system passed the test at default volt you should be fine. I use occt/memtest for testing memory