Corsair 4GB DDR2 XMS2 PC2-6400C5 TwinX (2x2GB) has different latency

Dela

Dela

Dela

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A month ago I bought Corsair 4GB DDR2 XMS2 PC2-6400C5 TwinX (2x2GB) which had timings 5-5-5-12. Then the other day I bought an identical pair but they had timings of 5-5-5-18 (even though they were advertised as 5-5-5-12) and I can't get all four to work together. None of them are faulty and I've tried upping the voltages and nothing. Any ideas? Thanks

My specs

Q6600 @2.4GHz
GA-P35C-DS3R motherboard
8Gb RAM (Hopefully)
7800GT
Vista Home Premium 64-bit
 
Dela said:
A month ago I bought Corsair 4GB DDR2 XMS2 PC2-6400C5 TwinX (2x2GB) which had timings 5-5-5-12. Then the other day I bought an identical pair but they had timings of 5-5-5-18 (even though they were advertised as 5-5-5-12) and I can't get all four to work together. None of them are faulty and I've tried upping the voltages and nothing. Any ideas? Thanks

My specs

Q6600 @2.4GHz
GA-P35C-DS3R motherboard
8Gb RAM (Hopefully)
7800GT
Vista Home Premium 64-bit
Click to expand...

I got some of the 5-5-5-18 and it run fine and 5-5-5-12, but that was only with one stick in. as one was DOA

4 sticks puts the memory controller under more stress, up the north bridge voltage a notch or two.

if that don't work, send them back if they where advertised as 5-5-5-12 because they are not.

EDIT: be very careful with upping memory voltages, as ram is very sensitive.
 
It's strange, I can run three of them to get 6Gb but when I add the 4th it won't boot. It's doesn't seem to be a problem mixing the RAM until I run it in duel channel. What's the north bridge voltage? Is that the voltage for the CPU? Sorry bit of a noob.
 
Yeah I tried upping the MCH voltage. I tried +0.1V and then +0.2 and nothing happened. Was a bit too chicken to go any further as it could only be upped +0.1V more and it would be at its limit (+0.3V). My motherboard won't let me change latency timings so there's not a lot I can do. It's already been RMA as it was advertised with the wrong info. Cheers for your help guys.
 
Hit Ctrl and F1 together on the main BIOS menu. That will unlock the memory timings in the MIT menu.
 
Well it did allow me to mess about with the timings but I still can't get it to boot with 4 sticks. It keeps turning off after about 10 secs then turning itself on again, then off etc... Never displays anything on the screen, it's just black.
 
Corsair have a habit of changing the chips they use quite often. They usually add them to this list, but it hasn't been updated since 12/11/2007 (that's possibly the 11th of Dec since Americans write their dates back-to-front. RamGuy says he'll update it again within a few weeks).

The only 2x2gb PC6400 kit I can see listed is the CM2X2048-6400C5DHX kit, and I'm not too sure it that's the same as the XMS2 kit you have (I have my doubts). And as you can see, the chips in the CM2X2048-6400C5DHX kit have been changed 4 times up to the 12/11/2007.

So it's very possible that your 2 kits are using different chips, and aren't compatible with each other.

Yellowbeard (a Corsair rep that regulary pops on here) would probably be able to confirm or deny this. Or you can try posting on that site to see if RamGuy can help you.

There is also an official Corsair support forum over at Xtreme Systems here that is monitored by Yellowbeard :)
 
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www.asktheramguy.com should be able to help.

I have the same modules as you except im running 2x2gb and 2x1gb and they run fine together: 6gb @ 1.9v 5-5-5-12 Dual channel.

What volatage are you running the ram at? The ram guy suggested I ran at 2.0v if I was had any issues. They said you can run the modules between 1.8-2.1v. You may need to increase the NB voltage but on mine it worked fine at auto.
 
Cheers for all your help guys. It has proved very useful. I think that the RAM is compatible with each other as I can run one of each in two banks (dual channel/ and not) and even two of one and one of another. It's only when all four are in use that it doesn't work. The computer goes into reset cyles every 10 seconds or so. It seems that some sort of under voltage is the problem, but that was the first thing I investigated. I've tried overvolting the RAM +0.3V hence it would be running at 2.1V (although Everest reported 2.0V) and still no joy. I'm gonna investigate it further and take on board all your help when I have a bit more time. Will keep you posted. Thanks again.
 
Dela said:
Cheers for all your help guys. It has proved very useful. I think that the RAM is compatible with each other as I can run one of each in two banks (dual channel/ and not) and even two of one and one of another. It's only when all four are in use that it doesn't work. The computer goes into reset cyles every 10 seconds or so. It seems that some sort of under voltage is the problem, but that was the first thing I investigated. I've tried overvolting the RAM +0.3V hence it would be running at 2.1V (although Everest reported 2.0V) and still no joy. I'm gonna investigate it further and take on board all your help when I have a bit more time. Will keep you posted. Thanks again.
Click to expand...

I had that constant reboot prob up until this afternoon, thats using 4 x 1gb sticks of geil pc6400c ULL memory in a gigabyte X38 DS5. No matter what I tried (and I tried a lot over the past few days) I couldn't get the pc stable. In the end I took two sticks out and I'm running orthos at 400 x 8 (3.2ghz) with ram at 1:1 (400mhz) for over 2 hours now. I reckon its more down to all 4 dimm slots being occupied than anything else, either that or not enough MCH (northbridge) voltage, but I tried upping that quite a lot and had no effect that I could see regarding stability. Just my two pence worth, hope this helps.:)
 
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