How to install a Graphics Card into a Mac Pro March 7, 2015 13:24
Incredibly useful is this handy guide to show you how install a graphics card in a mac pro by apple_cards
First off you'll need to make sure the computer is turned off and also that the power cable is removed from the rear of the Mac. Then remove the side cover by pulling the lever at the back.
Once the side cover is off you'll want to discharge any static electricity you may be carrying by simply touching the PCI blanking plates on the rear of the Mac. Also it's advisable not to wander around too much during the installation in case you start picking up any other static from carpets etc..
Next locate the two screws attached to the plate that holds the PCI cards in place. These are thumb screws and should loosen by hand but there is also a philips screw head to get a screwdriver in there should they not come loose by hand.
You'll want to make sure that any handling of the cards is done by the cards edges. Try not to touch any of the connectors or components on the card itself. If there is already a card in place you'll need to remove it. On Mac Pro models 2006, 2007 & 2008 there is a small catch where the cards edge connector plugs in that will need to lifted gently to allow the card to slide out.
Some cards feature either one or two PCIe booster cables that supply additional wattage to the card. There may be a cable already present that you can use but if not you'll want to install the cables if your new card requires them.
The connection of these cables goes from the logic board to the card itself with the logic board connector being located just under the second hard drive bay on the 2006, 2007 & 2008 models or to the lower edge of the visible logic board just in front of the PCIe fan on the 2009 onwards models.
These can be a bit fiddly to install but be patient and you'll get there!
Now it's time to install the new card!
Slide the card into place on the lower PCIe slot so that the card sits flush with the base of the PCI bay. This will by default be the x16 lane on all models of Mac Pro. You can of course install the card in another slot if need be (if multiple cards are used).
I find it easier to have attached the PCIe booster cables into the card at this point before sliding it in, but plugging them in after is not a problem.
Now replace the bracket with the two thumb screws and tighten to ensure the card won't move when plugging cables into the rear of the card. Tighten these by hand as they are not likely to come loose and it helps if you need to change the card out in the future.
Now replace the side cover and push the latch on the rear in to lock the side cover in place.