parani :
It doesn't make any difference. Its all compatible, no issues there
of course it makes a difference.
The advise is always to buy a matched kit to ensure compatibility. So two sets of the same DIMMS. They are sold as kits.
If you match one DIMM from one company and another from a different company, you may have issues with timings etc. You might have to play around with two different sticks of ram to get them to work together with no guarantee they will.