what's the RAM 'sweet spot' for PowerMac G5?

[cb911]

I'm just wondering - what exactly is the 'sweet spot' for RAM in the PowerMac G5's? Is there even a sweet spot?

I've been doing some reading, mostly this article:
http://www.macnet2.com/more.php?id=460_0_1_0
and they mention that 2GB used to be the sweet spot, but then they tried 4GB, made up of 512MB sticks, so they filled all 8 RAM slots, and they say they the PM felt and performed like a totally new machine.

here's an excerpt:

We took the 40GB movie project and moved it to the 4GB G5, and to be fair, we also moved it to the internal drive of 2GB G5 so that each machine would render them from their internal drive. Although the Maxtor One-Touch drive is fast enough to use for digital video it isnít as fast as using the Macís main drive.

Together we began the long process of rendering both jobs at the same time and left them both to do the work. We went out for lunch and returned two hours later. Unfortunately when we returned FCP crashed on the 2GB G5 but was still churning away on the 4GB G5. So we did it again. This time everything went fine and the 4GB G5 finished a full 47 minutes before the 2GB G5. (Both machines took in excess of 5 hours) Considering just how important rendering times are to people who do this all day, every day, the importance of more RAM becomes quite apparent.

It should be noted that a couple of days later we rendered the same movie on a 1.42Ghz G4 with 1.5GB of RAM and the amount of time it took to do the job was more than 100% longer than it took on the 4GB G5 (11 hours 20 minutes).

So has anyone tried this themselves? I've got no doubt that maxxing out the RAM is a sure way to increase performance when working with large files, and it would seem processes like rendering as well.

But is there anything about filling up all slots that makes performance better? Do all the sticks have to be the same size? Or would it be just as good to maybe have 1(or more)x1GB stick and 7x512MB?

And while we're on the subject, has anyone noticed particular brands of RAM that are significantly better than the rest? That article I linked to really sounds like a big Crucial commercial. People making comments on that site recommend Mushkin RAM more highly than Crucial. Thoughts?

I've been wondering about this for a while, so any comments are appreicated.
Oh yeah - I hope I posted this in the best forum as well...

 

[bigbossbmb]

I just added 2GB of RAM (2x1GB DataMem) to my G5 which already had 2.5GB (stock 2x256 and 4x512 Crucial) and the change was nice, but not nearly essential. Many programs (like ps, illustrator, after effects, etc) won't address more than 2gigs. Adding 2-4 gigs makes for a very good machine, I doubt I'd see much of a difference after that.