AMD 8131 Performance - Will 2 UAD-1's make a diffference?

[J]

I hope that one of the more endowed members of this forum can assist me with my query.

I currently have 1 UAD-1 card in a Dual 2.5 G5 Mac. Need to find a way to minimize this AMD performance problem.

Would purchasing a second card increase my ability to run more plugs or simply increase the likelihood of me hitting the roof of my G5's processor load?

Is there anyone out there who can compare performance of 2 cards over 1 with this AMD 8131 problem?

Should I purchase a second UAD now or just wait for UAD-2 (Whenever that is gonna happen!!!?!?!) ?? :?:

Help me, please!!

 

[MPC]

2 cards used to make matters worse in the effected G5's; so basically the 2nd card would take a bigger performance hit than the first, diminishing returns so to speak. That was back when I had 2 cards in the G5, around v3.6, I'm not sure if the later updates improved things, as I've moved my 3 UAD 1 carss to a Magma chassis.

 

[J]

2 cards used to make matters worse in the effected G5's; so basically the 2nd card would take a bigger performance hit than the first, diminishing returns so to speak. That was back when I had 2 cards in the G5, around v3.6, I'm not sure if the later updates improved things, as I've moved my 3 UAD 1 carss to a Magma chassis.

Thanks MPC. I guess what you are suggesting is that it's not worth buying a second card without a magma chasis. Am I correct?

How exactly does the magma chassis improve the situation?

Can anyone suggest whether the updates improved the situation with several cards and no magma chasis?

:|

 

[Trace]

There's a ton of info on this subject in other threads. What i'll say is that I think its worth while to get more than 1 UAD, even if you have a G5 with the bad AMD Chipset.

For one thing You'll be able to get more UA plugs going. The way the limitation seems to work is that its more noticeable the more audio streams you have. This means that if you use the more DSP hungry UA plugs you will come closer to the normal DSP output of the UAD than if you try to use a lot of the lighter DSP plugs ie EX-1.

The Magma helps but I can tell you that you won't get 100% from every plug. I Just re-did some tests with my system:
Dual G5 1.8Ghz PCI-X, 2.5 Gb of Ram
Yamaha O1X
7 Slot 33Mhz Magma Chassis with 4 UAD-1's

I set the MIN-GNT PCI Latency to 64
Running 24 Channels in Cubase SX 3, ASIO Buffer at 512, 44.1k
I've posted the most instances of each plug I could get to run stable with no G5 CPU spikes:

Dreamverb - I got 24, on a non-PCI-X G5, I should get 24- so that's 100%
CS-1- I got 40, on a non-PCI-X G5, I should get 40 - so that's 100%
Plate 140 - I got 16, on a non-PCI-X G5, I should get 16 - so that's 100%
Nigel - I got 8, on a non-PCI-X G5, I should get 8 - so that's 100%
Pultec Pro - I got 24, on a non-PCI-X G5, I should get 28 - so that's 4 less
1176LN - 28 Instances, on a non-PCI-X G5, I should get 32 - so that's 5 Less.
Fairchild 670 mono - 40 Instances, on a non-PCI-X G5, I should 48 - so that's 8 less
Pultec - I got 40, on a non-PCI-X G5, I should get 48 - so that's 8 less
LA2A - I got 56, on a non-PCI-X G5, I should get 80 - so that's 24 less
Cambridge EQ w/5 Bands & 2 Filters on - I got 64, on a non-PCI-X G5, I should get 112 - so that's 48 less
1176SE - I got 65, on a non-PCI-X G5, I should get 128 - so that's 63 less
The max # of instances I was able to get was 74 EX-1's 80 with high host CPU usage. Undrstand that I could get more instances from most every plug in but it would start to rob power from the G5 CPU’s, so I limited the # to the max with least effect on tthe host CPU.


TRACE

 

[J]

Thanks TRACE

Just read an article that suggests that real magma chassis improvement only happens when AMD 8131 mode is off. But this will put more load on UAD than CPU. Something about separating the AMD from the UAD. Can't seem to find a cheap magma at the minute anyway.

Anyhow, your input has been very useful and helpful. I will search for a nice cheap UAD-1 card and maybe invest in some alternative navtive plugs to alieviate the need for too many of those ex-1's on my tracks. (URS Classic EQ Plugs look neat!!) 8)

Thanks again


J

 

[J]

It's obvious that I didn't quite get it right with the whole magma amd 8131 thing so . . .

http://www.uaudio.com/webzine/2005/may/content/content5.html

Just incase a fresh repeat is useful to someone!!

 

[MPC]

I agree with Trace overall. If you like the UAD 1 adding cards to your 8131 G5 is still a pretty good answer IMO. The second card won't give you as much processing as the first, but will still add power. You could use that setup as a stop gap, if, let's say you were to buy a used Magma in the future. I've got 3 UAD 1 and a Powercore in my magma and I bought it for less than $300. It's really worth it. But, like I said, if for some reason you don't want the magma, a second card is worth the money IMO.

 

[UAJames]

Adding a 2nd, 3rd, 4th card in AMD-8131 machines will only increase your available DSP, *not necessarily* increase your instance counts. For example:

With 1 card in an AMD-8131 machine, you can get 4 Plate 140s or maybe 20 EX-1s. The limiting factor with the Plate 140 is you don't have enough DSP to run a 5th. The limiting factor with the 20 EX-1s is bandwidth through the 8131 chip. If you were to add a second card you will have more DSP; so in this example, you could get 8 Plate 140s, but would still only be able to get 20 EX-1s. Make sense?

Basically, if you are running out of DSP (not bandwidth), you will benefit from a second card. If you are topping out due to the bandwidth restriction, a second card won't change anything...obviously this is situation is different depending on the DSP footprint on the plugin. Users running higher sample rates will benefit from second cards since each plugin requires more DSP at higher sampling rates (so usually you will run out of DSP before hitting the throughput limitation).

 

[J]

Ok. That is a little clearer. Thanks. The way to minimise the AMD problem is to avoid using lots of lesser powered plugs, right? I still have a couple of questions.

Would I be right to assume that all plugs use the same amount of bandwith?

How exactly would having a magma chasis effect the scenario that you just highlighted?

Thanks for your time.

J

 

[J]

I got the second card!!!!

I notice improvements already!!! Especially when I replace some of my EX-1s with the URS N EQ plug!!!! I got the demo!!!

8)

I'm happy! This combo will do me till UAD-2!!!

Thanks for your help!!!