Yvan256 said:
My main concern would be/is what type of memory to buy? I've heard/read that Macs need a "special" type of memory (exemple: I've seen "CL2.5" on my PowerBook's RAM stick), stuff that the usual PC stores don't carry.
CL 2.5 refers to the CAS (Column Address Strobe) Latency of the RAM, it's a measure of how quickly the RAM can "get back in the game" after executing an operation. This measurement is common to all RAM, and on DDR RAM can be 3.0, 2.5 or 2.0 (lower being faster) The value doesn't make any difference to the Mac's performance, as it happens.
Dual-channel just refers to the fact you have to install two identical models as a pair when upgrading PowerMac G5s. It doesn't mean that the individual RAM modules are any different.
There isn't special Mac RAM. That said, there are other settings on the RAM module that can make it compatible or not compatible with a Mac. These are the SPD settings, and you will never see these advertised as part of a specification. Some generic RAM will be compatible, some won't. Some Macs are more tolerant of variation (PowerMac G5), and some are very picky (iMac G5, Mini, Powerbook 15" 1 GHz and 1.25 GHz, 17" 1 GHz and 1.33 GHz.)
So how do you tell by looking if a piece of RAM will be compatible with a specific Mac? You can't. You have to rely on the seller.
I recommend that you buy RAM from a reputable seller who tests and guarantees compatibility with your specific model of Mac, and offers a lifetime warranty.
Thanks
Trevor
CanadaRAM.com