I've been trying to get a handle on just how much power is used in a G5 and how much "power headroom" the beast has for expansion.

Reason for this is a rumour...from the audio world...that using an internal drive for audio tracking (i.e., laying down the individual audio tracks in a multi-track project) is such that the additional power drain on the G5 can allow for audio dropouts/glitches. Hence, the argument goes, one should use an external drive like FireWire (which has its own power supply, has become the industry standard in that one can easily remove the drives to bring them to another facility, 1394 is a universal connection, etc.).

Howsomever, there is still the somewhat nagging concern over the AMD PCI bridge chip issue wherein high PCI buss utilization compromises 1394 throughput (and there appears to be more than anecdotal evidence to this). I've also received the recommendation by _other_ knowledgeable audio people (and these more computer audio hardware types than recording types) that one should first use up all of the stock protocols/busses (e.g., internal SATA) before adding more onto the PCI buss.

So, I think to myself, maybe an analysis of the power draw in a G5 could at least put these things into perspective.

The doc:

(which is in the G5 FAq) shows that the G5 has a 600w power supply (which surprised me and counters a lot of the rumors that Macs typically don't have big enough power supplies).

I hope the above "parses". ;-)

Any input/thoughts on this? PCI cards have specs for power draws as do drives, but really, how much does the base system pull?

I've heard also that one 3GHz Xenon pulls about 85% as much power as _2_ G5s: (remember the ol' jokes when the Pentium first came out?)

"The dual G5 processors in the new PowerMac, both of them together, consume 97 Watts. The rated power consumption of a single Xeon at 3 Gigahertz is 83 Watts for a combined total of 166 Watts."

Which is arguably why PCs typically _need_ bigger power supplies than Macs.

Oh, and here's a page for the chip-heads out there ;-)

Thanks in advance!