What RAM is correct? Especially for "No hassles down the road"

To be honest, I think that 6 GB is more than enough RAM. But, if you think you really need it then I suppose...

How much memory is in those slots right now? I would think either 3x2 GB or 2x2 GB + 2x1 GB, if it's the second option then you won't have any room for expansion.

If your RAM is rated at 667 MHz, there's not much point getting 800 MHz or 1066 MHz RAM as it will run at 667 MHz by default, and if you try to set it any higher speeds then the original RAM rated at 667 MHz will be overclocked and may cause a crash.

Are you replacing the whole RAM kit? I.e., removing all the RAM and putting a new 4x2 GB kit of either 800 MHz or 1066 MHz?
If so then it should work fine without any problems seeing as the motherboard supports up to DDR2 1300 MHz. If your mother is not going to do any intensive tasks then 6 GB should be fine, if she's video editing or similar then I suppose the RAM upgrade is justified and since you're not doing any overclocking DDR2 667 MHz should be fine - just go for the cheapest RAM really.

Thanks Lmeow. I was just going to replace it so that just about everything is new. Everything except the
Q9300 and the video card. It' sabout two years old and since I was thinking of replacing the RAM, might as well upgrade. And it does have 2x2 GB + 2x1 GB. The Asus P5Q Pro Turbo MB. doesn't adjust for that automatically does it?
Thanks for the info, I was just looking for something staable and maybe a little more beefy. Maybe I should just leave well enough alone.