I have the same power mac as you, and yes you do have the 8131 chipset. But be strong! all hope is not lost. Adding a second card will indeed increase the number of plugs you can run. (I work at 44.1-48) I have two cards, in slots 2 and 3, and they work wonderfully, despite the 8131 restrictions. The 2.5ghz cpu is powerful enough that maxing out the UAD cards does not add considerable stress on the CPU at high buffer settings. At a buffer setting of 1024, in DP, I can run 14 instances of the 1176, which is about on par with macs that don't use the 8131 chipset. I can run 2 instances of the 33609, or load up the Neve on one card, and max out the other card with a bunch of plugs. I can run 6-7 instances of the neve 1073, 8 Plate 140's, 20 CS-1's, 12 Fairchilds...these are all on par with the non 8131. I can run only 32 stereo instances of the LA2A (compared to 36-38 with non 8131 macs), but adding a 33rd craps out the DSP. However, with 32 instances of the LA2A, i still have enough DSP to add 2-3 instances of the 1176LN! So just because you max out the card using a certain plug doesn't mean you can't fit more plugs on the cards (and in this case a plug even more DSP hungry than the LA2A, and, I NEVER need 32 LA2As!! I mean that's way too much color). And these numbers are for stereo versions...when mixing many of the tracks I record are mono.
On one project I was working on yesterday, I had 17 UAD plugs (mainly mono) (4 LA2A, 2 1176LN, 2 1073, 1 1073SE, 1 Plate 140, 1 33069SE, 1 Pultec Pro, 1 Fairchild, and some others...) and my system was humming at about 60% usage.
Make sure that in your UAD preference settings that \"Limit CPU\" is turned off. I get more mileage out of the cards this way. Also, although a hassle, if you have a big project w/ lots of plugs, you might get better results by \"assigning\" different plugs across the two cards manually. (This might not work, but i dont see why not!!!) In normal situations with multiple cards, any new instance of a plug will be automatically assigned to the card with the lowest amount of DSP usage. For example, if i have two cards, and card one is at 51% dsp, and card two at 49% dsp, when i load a new plug, it will be loaded on card two. But if you go into UAD meter, and disable card 2, you can max out the first card, then when you need more DSP, enable the 2nd card and start loading it up. I can't see this making a huge difference, but you might be able to squeeze one more instance this way.
For me, 2 cards was definitely the way to go. For bread and butter plugs, double the instance counts. For stuff like cambridge EQ, not quite double, but who needs 75 instances anyway??? Get yourself a good Native EQ, like DP's Masterworks EQ (sounds a LOT like the Cambridge).
W/ 2 UAD-1 cards, and a good assortment of Native plugs to fill in the holes, my G5 2.5ghz w/8131 chipset works wonders. If you need higher performance, there is always magma chassis...
