Two Graphics Cards in Mac Pro(2006). Any Benefits or problems?

[sngraphics]

I have a 1st Gen Mac Pro 1,1 (2006). It came with the ATI 1900X card with 512MB.
I just purchased the NVIDIA 8800 GeForce with 512MB and I haven't installed it yet.
Can't call Apple seeing I'm out of warranty.
Do I have to remove the 1900X or can I have them both installed?
Any benefit having both in the machine? (Not only for Photoshop CS5 but for any other reason? eg. system, running multiple displays etc.)
Any issues with having two cards in at the same time?
I bought the 8800 because I just installed Adobe CS5 and I am hoping it will help me run Photoshop better/faster.
Is there a difference between the 1900X & 8800 in regards to Photoshop CS5 performance?

Thank You in advance for any input.
Mac Pro dual 2.66, 8GB, 1900X, 1TB Hitachi

[AnimeFunTv]

I have a 1st Gen Mac Pro 1,1 (2006). It came with the ATI 1900X card with 512MB.
I just purchased the NVIDIA 8800 GeForce with 512MB and I haven't installed it yet.
Can't call Apple seeing I'm out of warranty.
Do I have to remove the 1900X or can I have them both installed?
Any benefit having both in the machine? (Not only for Photoshop CS5 but for any other reason? eg. system, running multiple displays etc.)
Any issues with having two cards in at the same time?
I bought the 8800 because I just installed Adobe CS5 and I am hoping it will help me run Photoshop better/faster.
Is there a difference between the 1900X & 8800 in regards to Photoshop CS5 performance?

Thank You in advance for any input.
Mac Pro dual 2.66, 8GB, 1900X, 1TB Hitachi

If I remember correctly, you can only have one 16x lane occupided, if you have more than two 16x lane cards one will have to be redused

[holyjohn]

I have a 1st Gen Mac Pro 1,1 (2006). It came with the ATI 1900X card with 512MB.
I just purchased the NVIDIA 8800 GeForce with 512MB and I haven't installed it yet.
Can't call Apple seeing I'm out of warranty.
Do I have to remove the 1900X or can I have them both installed?
Any benefit having both in the machine? (Not only for Photoshop CS5 but for any other reason? eg. system, running multiple displays etc.)
Any issues with having two cards in at the same time?
I bought the 8800 because I just installed Adobe CS5 and I am hoping it will help me run Photoshop better/faster.
Is there a difference between the 1900X & 8800 in regards to Photoshop CS5 performance?

Thank You in advance for any input.
Mac Pro dual 2.66, 8GB, 1900X, 1TB Hitachi

Mine's 1,1 too and I have 1900X installed as well.
But doesn't 1,1 MP have one cable for a graphic card?
Mine only has one cable....

[barefeats]

Photoshop has some gpu support but some pro users feel enabling gpu support actually slows it down. And two cards don't help. For more on this, see MacPerformanceGiude.com.

[sngraphics]

I appreciate all the responses.
What I am primarily trying to do with this switch is to basically work a little faster in Photoshop.
Specifically with larger files (100-400MB), Smart Objects, Gaussian Blur, Unsharp Mask.
These are my primary functions/tools I use. (of course there is more)
Will the 8800 help speed up these functions over the 1900?
I have been trying my own "tests" but I'm not a pro at this and need a little real world feedback from anyone who has experience with this specific upgrade.
If there is no boost going to the 8800 I'm just going to sell it.

Thanks to all in advance with any input.

[OptimusP83]

Unlikely you'll see a difference. But with both cards in your machine you will see one on you power bill! Ditch the 1900XT and keep the 8800gt in. Also I am pretty sure if you had both of them in, one of them would overheat.

[goMac]

Will the 8800 help speed up these functions over the 1900?

Not really, no. There are a lot of other places the 8800 will help, but Photoshop is not one of them.

You'd really need faster CPU's or a new machine with faster memory to increase those speeds.

[sngraphics]

Photoshop has some gpu support but some pro users feel enabling gpu support actually slows it down. And two cards don't help. For more on this, see MacPerformanceGiude.com.

I'm surprised that I saw you on my post. I'm a big fan of your website.
I actually frequented your site while in the process of deciding on getting the 8800.
In your April 24th, 2008 "3D GAME SHOOT 'EM UP: Legacy GeForce 8800 GT versus others" test,
in the opening paragraph you mentioned "We will add a future article comparing it to other graphics cards running Pro Apps."
I haven't been able to find this test. Was it ever done?
What I really need to know: for Adobe CS5 (esp. Photoshop) on 1st Gen MacPro
running 10.6.4, 8GB ram: what is the better choice the 8800 or the 1900X?