Power 2 Graphics Cards - Lack of PCIe

oliverj777

macrumors newbie
Original poster
Jan 7, 2010
9
0
England
Hello,

I've got 2 graphics cards for my Mac Pro, both require 2 PCIe ports, and of course my Mac Pro only has 2!

I was reading around forum, and I can get additional power by using this setup

Although, thats a lot of mess and effort for an extra PCIe. I was thinking, isn't it possible to feed the additional power from my second DVD slot (not used)?

Or even use Y splitters (personally, I don't feel safe using this method though)?

As my main Graphics Card, I have the ATI Radeon HD 4870 512MB thats powering a DELL U2410 Ultra Sharp, and an ordinary DELL E176FP (classic office style).

My secondary Graphics Card, is a ATI Radeon X1900 XT that 'used' to power also another DELL E176FP. Although, when I upgraded the Mountain Lion, I get nothing through it, just a warning message about the lack of power... Before, I used to also get that message, but it would still try and power up.

Anywhoo, please give me your expert advice. Oh, and its a MacPro Quad-Core Intel Xeon 2.26GHz.

Thanks!
 

goMac

macrumors 604
Apr 15, 2004
7,036
1,056
I'd consider just replacing them with two 5770s. It's a better setup, and it's going to be less mess.
 

ActionableMango

macrumors G3
Sep 21, 2010
9,511
6,695
In fact a single 5770 can run all three of those monitors, although you may need active adapters if the monitors don't have display port.
 

Mac_Max

macrumors 6502
Mar 8, 2004
404
0
Wow, that is seriously overkill.

The Mac Pro PSU comes in at ~1000W of total power and is a very good quality unit. Overclocked PCs with similar hardware specs have no problem with that many GPUs. I'd suggest just getting the splitter and calling it a day. You're not going to hurt the PSU. If you were to overload it, (which with 1KW of power and limited expansion bays/slots.... not likely) the over-current protection would kick in and turn off the computer before any damage would occur.
 

DanielCoffey

macrumors 65816
Nov 15, 2010
1,189
24
Edinburgh, UK
It isn't the rating of the PSU that is the issue here... it is the rating of the cables and traces that are delivering that power from the PSU to the graphics cards.
 

oliverj777

macrumors newbie
Original poster
Jan 7, 2010
9
0
England
Graphics Card Upgrade

Okay,

I am contemplating on getting the 5770, but just I have a another question. Whats the difference between this card, and this card.

They both have the same name, yet they look completely different?!
 

ActionableMango

macrumors G3
Sep 21, 2010
9,511
6,695
One is made for Apple and works perfectly in the MP. The other is made for PCs and could be flashed to work in a MP.