whats better?

Having 2 sticks of 512MB PC-4200 RAM for a total of 1GB running with dual channel, or having 3 sticks of 512B PC-4200 RAM not running with dual channel?
I know the 3 sticks would give you more memory but it would be slower than the 2 sticks with dual channel.

 

If you want 2x512(1GB) I would just get 1 stick of 1GB so you don't use up valuable memory slots with 512 sticks. You will be able to have more memory in the long run.

 

Since your board apparantly supports dual-channel, I'm thinking you probably have four ram slots available on the board. I'd just use the two 512s you have and take advantage of the dual-channel option. Store the extra 512 untill you can aquire another one of the same make and model - then you can go to 2 GB of dual channel ram.

If you only have three ram slots available, if it were me I'd still go with only two. However, I don't actually know the performance specs on dual channel vs. standard, so it might be a good idea for you to try both configurations and run some bench-marks, etc. and see what works best for your particular set-up and the programs you use the most.

I will say that when I went from 512mb to 1gb of ram, I noticed a huge performance increase on a non dual channel system. I then added another 1gb later for a total of 2gb, and didn't gain that much of difference in overall performance.

Good luck.