Mixing memory

[allenthehobo]

Right now, my desktop has 1 gig of memory, 2 sticks of PNY 512 mb, DDR400. I'm looking to upgrade to 2 gigs, but my motherboard only has 3 slots for ram, which means that I have to stick in a 1gb stick. The questions are:

Can I mix different brands of ram? PNY 1gb sticks are damned expensive. =[

Can I mix different sizes of modules? The 1 gb + 2x512? Will any problems blow up my comp? =O

Thanks.

 

[alcoholbob]

Probably, but I would be prepared to raise the timings if needed if problems arrise from IC incompatibilities, etc.

 

[InlineFour]

mixing memory brand and size is fine. however, you should keep the memory speeds consistant. (pc3200, pc2100, etc)

 

[andyandyandy]

In some cases yes, although i mixed a 512mb generic with a 512 mb kingston (both ddr400). It didnt power up. They were not compatible at all. So i guess be careful

 

[mshan]

I've got a questions about "dual channel" memory:

I just got my dad an Apple iMac (Intel Core Duo), which has 512 MB memory stock.

It has a second memory slot, is supposed to support dual channel memory, and the manual says you can add either 512 or 1 gb memory.

For dual channel, does the physical construction (e.g. number of memory modules on each side of the dimm) have to match, in addition to overall specs?

Also, anyone know how much of a hit I will take by using an unmatched 1 GB stick with the stock 512 MB stick (vs. simply adding a second 512 MB stick)?

Any insights would be greatly appreciated!

 

[imported_Imp]

I do, and I don't recommend it. My DDR400 Ram only runs at craptastic DDR333(won't POST) because of my mixing of different CAS sticks (same model Corsair Value Select but one is CAS 3, the other is CAS2.5; didn't know exact meant exact down to revision). So you may be lucky, but I personally won't take that chance again.

 

[allenthehobo]

Okay... So is there any "guide" or rules to mixing memory that I should follow? I know don't mix PC####, but maybe no generic ram withgood ram? =O

 

[alcoholbob]

In general the best advice is the sell what you have and try to get matched pairs. Most people would rather not do this (including me), which leads me to quite a bit of indecision as my RAM is pretty good, pricy when I got it, and I wouldn't get much money for it now (Corsair 3200XL 2-2-2-5 RAM). I bought an extra stick which worked (booted) and I could surf with it, but crashed every time I played a game.

I didn't find this out until I was past the 30 day return. I found out Corsair has 1.1 and 1.2 variants of all their XMS RAM with different integrated controllers which makes mixing impossible despite identical speed (400MHz), timings, and PCB. Since dual-channel memory systems came out, it's been nothing but trouble for a lot of users.