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TzunamiOSX

macrumors 65816
Original poster
Oct 4, 2009
1,067
445
Germany
680 GTX as example.

When I don't connect the GPU to the two 6-pin connectors and then start the computer, what would happen then?

- computer does not start?
- damage the computer?
 
If the 680 has two 6-pin connectors itself, you will be fine since the Mac Pro can power a card with two 6-pins safely.

If the 680 is a 6-pin and 8-pin card (which will require you to use a 6 to 8-pin adapter), you will be exceeding the Mac Pro specification and *may* damage the computer in long-term use.

If the 680 is an overclocked 2x 8-pin then you would be highly likely to damage the Mac Pro very quickly. At best you would get unexpected shut downs. At worse you would ruin your logic board.

This topic has been discussed extensively and you will find a lot of information if you search.

There are some good 2x 6-pin 680s such as the MSI 680 4Gb Twin Frozr card if you want one or you could buy a modified 780 from MacVidCards on eBay.
 
680 GTX as example.

When I don't connect the GPU to the two 6-pin connectors and then start the computer, what would happen then?

- computer does not start?
- damage the computer?

im currently using 2 x 6 pins into a 4gb 680gtx which has a 6 + 8 .. no issues .. will be doing the same with a 780gtx soon.
 
680 GTX as example.

When I don't connect the GPU to the two 6-pin connectors and then start the computer, what would happen then?

- computer does not start?
- damage the computer?

I'm curious why you don't want to hook up the two 6-pin connectors? Do you already have another card that is using them?
 
If you're using an external PSU just make sure it's running before starting the computer. Starting the computer without the GPU powered won't hurt anything though, you'll just have no video from it.
 
If you're using an external PSU just make sure it's running before starting the computer. Starting the computer without the GPU powered won't hurt anything though, you'll just have no video from it.

This is what I want to know. If I use a Aux PSU (Booster X5 for example) and the PSU dont start with the Mac (defect or no cable), will this kill the GPU or board.
 
Have a search for the external PSU threads on the forum - there are good discussions about it and how to connect the original and external PSU so they come on together.
 
If you look in the top right of the Mac Pro forum you will see the Search This Forum button. Try "External PSU" and see what you get.

I know there is a thread titled "GTX 780 with External PSU help" which will lead you to your answer.
 
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