[steve626]

I read somewhere about "matched RAM" being better than unmatched RAM. For instance, I purchased a new iMac G5 in June with 1.5 Gig RAM, which consists on one 1-Gig + one 512-Meg chips... these are clearly "unmatched RAM" because the two chips are different sizes. I do recall some discussion of 128 bit versus 64 bit performance (matched RAM -- 128 bit-- versus unmatched RAM -- 64 bit), but then read about tests where no difference could be seen in real life tests running actual software on the iMac.

I think the extra RAM I got, 1.5 Gig versus 1.0 Gig -- the latter consisting of two matched 512-Meg chips, reduces paging to disk which I think is orders of magnitude slower than some infinitesimal speed increase from having matched RAM. I don't understand about the 128 or 64 bit paths.

Is there a utility that tells you if your memory is using 128-bit versus 64-bit?

[P]

Search this forum and the Powermac one for details on this, including exactly what happens - I know I've explained it in detail at least once. Short version is that the gain from using matched RAM is extremely tiny unless you're doing something that really fills up the memory bus, so you're probably better off with 1+0.5 gigs.