RAM pairing questions

[Destinatus]

I did look at the FAQ and couldnt find it there but it might have been mentioned. I know that it's ideal to pair your sticks, but what about 3 matching? right now I have 2 1GB corsair sticks and I found a pretty good deal on a 1GB crucial stick that has all the same specs. Would it be okay to get one or should I get 2 so that it would be 2 pairs (4GB)? I do a lot of photoshop work at high resolutions so I could probably put it to use, I just dont really want to deal with the 64-bit Windows stuff. Thanks

[LeftyAce]

keeping things in matched pairs allows for dual channel operation. Since you're using 32 bit windows XP, you won't see more than 2.7 or 3GB of ram anyway, why not get two more 512 sticks so that you have 3 G, all dual channel? All four don't need to match, just the pair on each channel.

[Destinatus]

32 bit Vista actually. My friend said he has an extra copy of 64 bit that he would let me have. The deal is only for 1gb, so I guess my question now would really be how bad is Vista x64? I hear theres a lot of issues with lack of support for it.