ATI 4870 + ATI 3870 in 2008 Mac Pro - my potential solution

[MacVidCards]

Yes, 3870 DOES require a power connection.

You can either use a Molex to PCIE or a SATA to PCIE depending on what power source you wish to use.

Or get a PCIE splitter.

Not good for 3870 to run unpowered.

 

[ryanschmidt]

Yes, 3870 DOES require a power connection.

You can either use a Molex to PCIE or a SATA to PCIE depending on what power source you wish to use.

Or get a PCIE splitter.

Not good for 3870 to run unpowered.

How bad is it for it to run unpowered? It's been running 1 display like that for months.

Out of those options, which is the best? I couldn't find an sata to pcie.

 

[ryanschmidt]

Will this cable work? http://www.performance-pcs.com/catalog/index.php?main_page=product_info&cPath=186&products_id=2664

 

[MacVidCards]

Will this cable work? http://www.performance-pcs.com/catalog/index.php?main_page=product_info&cPath=186&products_id=2664

That will work nicely. I would split one of the 4870s power cables to both 4870 and 3870, spread the load, as it were.

 

[ryanschmidt]

That will work nicely. I would split one of the 4870s power cables to both 4870 and 3870, spread the load, as it were.

Well, I received the cable today. I plugged it in like you said and heard a noise. Since then, the video card hasn't worked correctly. I'm pretty sure it's done and I'm ready to order another card... but just to be sure, here's my issue:

the computer boots with all 3 displays as it should. I bought the cable so that I could connect a 4th. I never even got that far yet. So the computer boots just fine. It will work just fine for a couple minutes and then the two displays plugged into the 4870 die and the computer freezes. I can barely move the mouse, etc.

I am now using the 3870 with dual displays and it's working just fine. Thank God the Mac Pro is still OK.

So, out of luck? Replace the card and move on?