
Im using 4 sticks, used to have 2 geil and 2 OCZ platinum edition. I had to change the timings and frequency in BIOS to get them both working together, but other than that I had no problems.
Now I have 4 sticks of Geil after trading with a mate and didnt have to mess about in BIOS at all with them, so its just a lot less hassel getting matching sets.
I'm using 2x Ballistix PC5300 and 2x GeIL PC6400 together at 1.8V or 1.9 @ 850Mhz 4-4-4-12, seems fine even though they are mixed.
