G5 CPU performance (PCI-x vs. PCI)

[paulk]

Hey all,

Over a year ago I've purchased 2 UAD-1 cards and installed them into my G5 (Dual 2.0 GHz, PCI-x).
I was sure that powered plug-ins will not load my host CPU at all; and that I'll be able to run a virtual mixing console (32 channels with EQ and compression on each) with low buffer settings and keep my DAW responsive.
Unfortunately, it never happened: the powered plug-ins seem to load the host CPU just as much as non-powered high end plug-ins, such as T-Racks EQ and Compression. This makes my setup kinda worthless: having 24 channels with Cambridge EQ and 1176 on each gains my CPU load to 70% - 80%, which makes my application work slowly and affects it's graphic performance and a whole workflow in general..

I've contacted the UAD tech support and they've explained that my mac has a notorious AMD chipset which involves CPU resources on each plug-in instance.
Also they've mentioned that the PCI (not PCI-x) model of G5 has a way better performance with UAD cards, but the didn't tell if that applies to the host performance (CPU load) or to the UAD performance (number of powered plug-ins I can use)..

Now I'm considering to switch to a used PCI G5 and here are my questions:

Is it typical for powered plug-ins to use host CPU resources? Or does it only happen with PCI-x G5s with that AMD controller?
Does anyone have any good experience running 32 channels of powered plug-ins in one project with multiple UAD cards on a PCI G5 with low (256Kb) buffer settings? And what did host CPU meter look like in this situation?

Thanks,
Paul K

[NEWRIGEL]

PCIe is better. You should go there if you don't want the issues. Or, since your thinking of upgrading... a new Mac Pro would kill your issues altogether!
Is it a $$ thing? if it is then a 1,1 Mac Pro would be a HUGE difference from a PPC and you can pick them up for $800 US!

[paulk]

thanks NEWRIGEL!

unfortunately I can't go for PCIe at the moment: to many things to upgrade:
- mac with new RAM etc.
- two UAD-1 cards -> UAD2.

My demands are pretty basic: 32 channel console-style operation with EQ and dynamics (or SSL or NEVE strip) on each channel and no host plug-ins at all. And I to save host CPU power for automation, smoother graphics, video playback and other tasks.

Switching to intel or to PCIe mac sounds like a great idea, but I just can't afford both mac and UAD upgrades at the moment.

Would be great to hear from someone with good experience of PCI G5 mac running lot's of plugins.