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Multiple UAD-1s and PCI-X G5s? Magma expansion the solution?


New Member
I'm new to this forum so excuse any repetition from previous posts.

I understand that there is a conflict between UAD-1 cards and the PCI-X controller chip on PCI-X macs, which limits the available DSP. It seems that one card is worthwhile but that the inefficiency is increased when multiple cards are used, perhaps even reducing the available DSP as a second card is added. My questions are;

a) Have I understood the issue correctly?

b) If multiple cards are run through a Magma expansion chassis, does this overcome or improve the problem?


Dual 2GHz G5, 2Gb RAM, Lynx AES 16 PCI card in slot 2


Active Member
a) yeah, pretty much.

b) Magma helps. In my experience the PCIX problem causes about a 15%-20% hit in UAD-1....I use a magma and I'd estimate I get about 10% of it back.....but, UA has been pretty diligent about trying to improve this, so things may be better now. Last time I had a UAD1 card inside the G5 it was with version 3.6, so with 3.8 results may be better, perhaps someone else is better setup to answer that.


New Member

Thanks for the reply. I'm glad things seem to be working for you. Could you let me know the following

What sequencer are you using - Logic - Nuendo etc?

What computer?

What model of Magma?

How many cards in the Magma?

Thanks very much


Active Member
I'm using a Dual2.5 G5, 3.5gig RAM, 2WD Raptor HD. Nuendo3 and DP4.5 are my sequencers. 7slot Magma 33mhz, I believe, it's one of the ones that won't work with HD so people are letting them go cheap, got mine for $275. It has 3 UAD 1 cards and a TC Powercore. I'm also using a 2408mk3 with some external converters.
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