Problems with 4 x CM2X1024 6400 C4 in IP35 Pro

[Mutley]

Hi,

I have an Abit IP35-Pro mother board with 2GB of PC6400 XMS2 RAM (two sticks of 1GB), the 6400 C4 stuff, and its been working flawlessly (this RAM runs at 4-4-4-12 by the way).

I just added another 2GB (i.e. another 2 sticks) last night, and the system is no longer stable - BSODS, lock ups etc.

The CPU is an E6600, and everything is at stock speeds. I noticed that the RAM I installed yesterday is "6400 C4 G". Does the G make a difference, could that be an issue?

The other thing I noticed was that in CPU-Z, the serial number and manufacture date are not reported for the new RAM (as they are for the old) - dunno why.

And finally, CPU-Z reports that trc value as 102, where as on the old RAM its 22. I think it should be 22....however, I have no idea if trc really matters. In the BIOS, the setting for this is auto. If I manually set it to 22, the machine won't even POST.

One final thing, I ran both sticks of the new RAM (without the old installed) through Memtest86+ last night (18 passes) with no failures.

This does look a little like this thread :http://forums.hexus.net/pc-memory/14...-ip35-pro.html
but my RAM is only running at 800Mhz as it is....

Any thoughts?

EDIT : I found this thread :
http://www.asktheramguy.com/v3/showthread.php?t=63003
Sounds very similar. If I change the RAM speed to 667mhz down from 800Mhz, how much of speed impact will that be? And why can't the memory controller handle 4x1GB sticks at 800mhz...

Mut.

[Yellowbeard]

On this board, you'll need to adjust the memory controller voltage to compensate for the load of 4 up. Work up slowly from the stock amount.

[Mutley]

So, its at 2.1v at the moment - thats the RAM voltage currently - thats what you mean?

Also, does the "G" mean anything, at the end of the name?

[Yellowbeard]

No, I'm not talking about the RAM voltage. Your memory controller comes stock ready to run 2 modules in dual channel. When you go to 4 modules, you need to compensate for this with a bit of extra memory controller voltage.

"G" is a letter added to indicate GREEN aka lead free solder.

This may help some also, read AN806.

[Mutley]

Thanks, your help is much appreciated! I'll give this a go when I get home from work...
Mut.

[Mutley]

Still struggling with this.

I've tried upping the MCH voltage from 1.25 to 1.37 (with steps along the way). So far, no luck, still unstable. Its better, but not much. I've also tried pushing the RAM voltage up a bit at the same time, but no luck there either.

If I drop the RAM speed to 668, everything runs fine.

Is it worth continuing to push the MCH voltages (sorry, this is new area of exploration for me, so I'm not sure what makes a "safe" voltage), or run it at 668Mhz?

What speed difference might I see (from what I've read, probably none)?

What impact would that have to overclocking though...?

Thanks again
Mut.

[Yellowbeard]

You should be able to go to the 1.4v to 1.45v range safely. And, you won't see a huge difference in running at the slower speed unless the slower speed is causing you to reduce a CPU OC. If your CPU is the same speed at both memory settings, then the performance will be similar. Probably about 5% better at 800 vs 667.

[Mutley]

OK, back to this again...(been away travelling for work).

I've pushed the MCH voltage to 1.44V and the RAM to 2.125....so far it seems stable, and this is running at 800Mhz and 4-4-4-12 timings...Hopefully that should do the job.

Mut.

[Mutley]

Spoke too soon.
Up to 1.48v for MCH and 2.175 for RAM, and still blue screens. Not keen on going to higher voltages - anyone got any suggestions?

[Yellowbeard]

Test each memory module at its stock timings and rated voltage for 3-5 passes each. Let's make sure you don't have a module that may be failing.

www.memtest.org

[Mutley]

OK I'll give that a go...I already did these tests, running two modules at a time at stock timings, with no issues, but not one at time, although I wouldn't have thought that would be any different.
Lets see what happens....

[Yellowbeard]

OK I'll give that a go...I already did these tests, running two modules at a time at stock timings, with no issues, but not one at time, although I wouldn't have thought that would be any different.
Lets see what happens....

If you have already determined that the memory is not faulty then there is no need to run the tests again. Also, if your memory is testing OK, then you may want to contact ABIT tech support. As RAM GUY noted, the MOBO and memory controller may simply not be able to run 4 up at DDR800. You may need to run them at 667. Since you are not OCing the CPU, this will not be an issue.

[Mutley]

Thats what I'm wondering.
Thanks for all your help, much appreciated.
Mut.