I have: 1 x pc3200 512 DIMM, OCZ
I have just bought: 1 x pc3200 512 MB DIMM, Crucial.
As of now, I switched out the OCZ and put in the Crucial, and everything seems to work, but when I have both in there, the computer would crash after a while. I’ve looked in my motherboard manual and there’s no indication of any particular order they have to be installed in.
What gives?
Subtle timing differences, most likely. Ram can be like that - the specs are the same, but it just does not quite work together. I always buy RAM in manufacturers pairs.
Check for a BIOS option to disable Dual-Channel. This effectively interleaves the memory accesses across the simms to improve memory throughput (odd addresses on the Crucial, even addresses on the OCZ). If the timing is a bit off, then you can get errors. Disabling Dual-Channel will just use bank access - low addresses from the Crucial, high addresses from the OCZ. This is slower, but can be more reliable.
Get a MemTest boot cd (download and burn the ISO) and run the machine in all combinations (Crucial, OCZ, Crucial/OCZ, OCZ/Crucial with Dual-Channel on and off) - you’ll get to figure out where the problem is.
Si
How’s the space around the memory sticks? If they’re too tightly packed together, the sticks in the middle may be overheating. This happened to me when I got more memory - the four sticks were packed like sardines. I solved my problem my lowering the memory speed slightly.
ETA: Or it could be what si_blakely said.
This matches my limited knowledge. As far as I know, dual-channel ram sets are only reliable in tested (packaged) pairs. If you have more than 2 slots you can try putting the cards into non-paired slot. On intel boards at least, the paired slots are next to each other, with each channel marked blue or black, so you’d have black, blue, black, blue and you could for instance put both cards into the blue slots if you don’t want dual channel operation.
Hmm, I have 3 slots, all of the same color…
Oh bah. The OCZ stuff is CAS 2.5, the Crucial is CAS 3.
You should be able to set the memory access timing to the slower value in the BIOS. It sounds like your m/b does not do dual-channel anyhow - the three slots thing is a bit of a give-away.
Good luck
Si
When you install different speeds of RAM the faster stick will (should) automatically fall back to the speed of the slower one. You can be sure it is doing so by setting the speed in your BIOS; watch the screen when the machine begins to boot and you will see a message something like “Press DEL to enter SETUP.” Setup is where you want to be, the key to press varies by manufacturer, and lower end boards may not have a manual setting for memory timings.
The three memory slots do run dual channel mode. Two slots use the same size sticks, the third slot needs to have double the size of the other two to run in dual channel mode, e.g., two sticks of 512 and one stick of 1024.
You will need to look in your motherboard manual to determine which of the slots are assigned to which bank of memory; it does matter. If you can’t locate your manual, you can just try every combination of the slots to see if one of them works.
Well, how about that. After finally giving up on the memory last night, my hard drive decides to eat itself.
Anyway, I spent the morning re-formatting and reinstalling. I am now running with both sticks in, one in bank 1 and one in bank 3. I don’t believe the MB has dual channel, there is no option in the bios for it, but I will have to confirm the CAS.
Stupid computer.
Well Fuck.
If I have the CAS 3 RAM in, I can set CAS bia the BIOS. If I have the CAS 2.5 stuff in, the CAS locks to 2.5. Even if I have the CAS 3 ram in as well. No amount of diddling with the BIOS settings resolves this. I have already re-flashed to the newest version.
:smack:
Try switching the memory sticks around. The BIOS could lock on to whatever is in the first bank.
Already did. Still goes straight to 2.5.