I have 3GB of RAM in my Mac Pro (the two 512s that came with the machine and a pair of one gigs) RAM is relatively cheap now and I'm thinking about adding another four. I posted about this on the Apple Logic Board and one guy said I shouldn't expect to see any noticeable change in speed, but it would be very helpful when I ran a lot of plug-ins, etc. True? I've always heard the more memory the better, but what does this mean exactly? Another guy said that Logic works better in multiples of 4Gig RAM. He said I should add one gig or five gigs. Another guy wrote suggesting there wasn't a strong scientific basis for that. Anybody have an opinion on this?

Hi Prince, couple of things here. As far as I understand it, installing RAM in these things is all about pairing between RAM modules as well as the risers. Not only that, applications such as Logic to date can't access more than 3GB of RAM and the operating system has a limit of 1GB or something anyway so some would argue that getting more than 4GB is a waste. When everything is coded to go 64bit then that will change. How you install the RAM also makes a difference. With MacBooks, MacBook Pros and iMacs you are advised to install in matched pairs for max performance. The same deal applies to the Mac Pro but depending on how many RAM sticks you have will depend on where you put them because you have more than 2 RAM slots. If you were going to use 4GB then the most performance will be gained from 8* 512MB chips in both risers. If you were to get 8GB then 8 * 1GB. If you want to grow in to something because getting 8 512MB is daft really, then 2* 1GB in riser one and the other 2GB in riser B will be better than 4GB in riser one. There is a link on the apple support site that tells you all about it so I'd recommend you go and have a looksee.