Is it ok to mix RAM brands?

[toni007]

I have 4 GB of RAM total.
But only 2 GB installed because i have Corsair Dominator 1GBx2 and i had before 2GB Pq1 800U
i have 2 RAM slots on motherboard,so i can install max 4GB of RAMS
I was thinking of mixing 1 Corsair Dominator 1GB with Pq1 2GB so that i have 3GB of ram instead 2GB?
Both are DDR2 Ram,Corsair is 800Mhz.
I don't know what mhz pq1 have?
but it is pq1 800U?
Maybe 800U means 800mhz?
I was wondering is it ok to mix Corsair and Pq1 RaM? Corsair has HEAT XCHANGER and this one does not.
Could i mess my pc,hurt it or something by testing it?
I would appriciate some advice.

[Arclight]

Yes and no. It won't damage anything and possibly works fine, but mixing different modules is generally discouraged. Both modules should run at the speed of the slowest module, but I can't say for certain the timings get adjusted as well. Unless you have an enthusiast board, you likely won't have access to those settings. Modules with different timings can cause some trouble, though as far as I know it results in BSOD so you'll know quickly enough.

[toni007]

I have put 2GB pq1 and Corsair 1GB and i have booted and so far no problems?
it says in system 2.99 GB of RAM
How can i test if they will work in future?

[toni007]

It seems they are diffrent
Corsair is
5-5-5-18

and
CM2X1024(PC2)-6400

pq1 is
5-5-5-15
PC2-6400


corsair is 1.9v and pq1 1.8v (will this diffrence cause troubles) and both are 800mhz
they are both Non-ECC, Unbuffered


and it still works?
What can happen to my pc?
can diffrent brands fry something or hurt my pc?

[Arclight]

Brands, no. Timings can cause trouble in terms of stability, but no damage. Voltage is something to check though, more voltage than it is designed for is what can cause damage. RAM voltage is global; see if things are stable at 1.8v, maybe try 1.85. You can run 1.9 if you must, though I'd feel a bit uncomfortable over-volting a module. It might cause no trouble at all or it might fry the module, hard to say.

At worst, at least in my experience, you kill the pq1 module (if you run 1.9v). Today, tomorrow, 3 years from now, impossible to say.