Radeon R9 280x on Mac pro

No, it came with one 6-pin and one 8-pin. The card doesn’t work at all with only one cable. I thought one should be enough when I installed it, but the fans didn’t move at all then. When I use another cable, a white hdmi-minidisplayport it works fine, but then I only get 30 Hz, which gives you flickering when you move windows on the screen. I have bought another cable with minidisplayport in both ends, ready for 4K and 60 Hz, maybe it will be better with that.

Hello! I have just installed AMD Radeon R9 280x in my Mac Pro mid 2012 Quadcore. The computer can't be used anymore when it is blowing and whining every time I turn it on and the screen, HP z27s, is gray and flickering. Do I have to change power supply? I am so disappointed. There was no info about this on eBay where I bought it. Trying to get old technique to fit new hardware is hopeless.

With regards

Pär Nordqvist, Sweden

a white hdmi-minidisplayport it works fine, but then I only get 30 Hz,

If you get a picture under any circumstances, then the card is mostly working.

The slot is said to provide about 75 Watts. Each six-pin cable is said to provide about 75 Watts. Eight-pin cables, backed by larger-sized wiring, are said to provide 150 Watts.

When you overdraw the Mac power supply by doing something very graphics-intensive, your Mac may suddenly power off to protect itself from the overdraw (overdraw seems to the power supply like a giant short-circuit).

User Tip: Mac Pro silver tower (2006-2012) Replacement Graphics cards

It requires more power than the two 6-pin cables (you would have to buy at least one assuming you have one already).

check out the 7970 which I assume is more commonly being used - though still only a small handful % of users.

Cards that need an 8-pin power cable often can mean needing a small but extra 450W PSU.

All these cards require flashing for boot screen and full for full 5GT/s linkspeed they require flash and removal of a small resistor. http://forums.macrumors.com/showthread.php?t=1547340

You can go for a 6 pin to 8 pin adapter for these cards. A lot of people report that these cards run fine like that and won't damage your Mac's power supply or mainboard.

To be on the safe side you could do this:

- get 2 x SATA power to 1 x 6 pin power adapter

- 2 x 6 pin to 1 x 8 pin power

This way you will get full power requirements for these cards without going over the specs of Mac Pro PSU and Mainboard power connections. But you will lose 2 x SATA ports on the board.

Visit netkas.org etc. for more information before you do any of this 😉

On netkas.org

I got a XFX R9 280x Black OC addition. Could not get it to work in my 2009 mac pro. It comes with an 8 to two 6 pin cable. I also bought a 8 to 6 pin adapter. So far I have had no luck, I have a second video card installed so I can get the boot screen and get a system report. The fans spin on the new card but it never shows up in the report. I have been on netkas and searched around. Barefeats got a 280x from a different manufacturer using the Eight to six adapter and the other six to six. But that has not worked for me with this card, so I am returning it.😟

I new it was a bit of a test and it might not work. You can buy a flashed one from MACVIDCARDS on ebay, but its pricey compared to the stock card and there is only a slight speed bump according to barefeats having it flashed.

So back to the drawing board. The R9 is cheaper than the older 7970 but they are essentially the same card.

The black addition may be the reason it doesnt work and maybe the cheaper version would... don't know.

Still wainting to here back from a few folks before I retun it.

Just thought I would share my experience so far.

What other gpu you said you have in there? I assume it does not use any extra power which would mean GT120 OEM likely.

Also - the assumpion is you have OS X version to support this card too (10.9.2+)?

Ideal would be to hook it up to a 450W external PSU $35 from Newegg or Amazon.

You can send the card to Macvidcards and have him handle flashing etc and maybe even test - but at least ask him . Then decide if you need to exchange it (or return outright).

Barefeats probably is using an added power supply or not?

Hi Hatter, Barefeats used the internal power supply, and macvidcards states his flashed card works with two 6 pin cables, which I dont get but maybe he provides a 8 to 6 pin modded cable and aonther 6 pin to 6 pin. They run both run them off the internal power suplly.

I have emaild macvidcards about flashing it for me and about my issues, waiting to here back from him.

Also I have been testing it under 10.9.2 but no luck.

My other card in slot 2 is the ATi 2600xt which needs no power.

Ah, yeah, have seen your post on Netkas.

There's only two, no three possibilites, as far as I can see:

1. Your card is broken. Dead on arrival 😉

2. It doesn't get enough power ...

3. or it doesn't detect power on one of the cables correctly.

So either your 6 pin to 8 pin adapter is not the right one. Not the right setup of power lines and grounds.

Or it doesn't get enough power in, which should not be happening in Desktop / 2D only. It should at least boot up.

Be advised that, also a lot of people say they run their 280x / 7970 from internal power only, your are OVER the maximum the Mac Pro can safely supply. The Mac Pro gives you 1 x 75 from Slot, 2 x 75 Watt from 2 x 6 Pin on the board. Thats 225 Watts. The 280x can easily draw 250 Watts and spike to even more. The card is designer for 2 x 75 Watts = 150 Watts: 300 Watts.

The Mac Pro has the power lines as traces ON THE MAINBOARD. So if they overheat / fry: there goes your whole board. And I've already read that a couple of times from people. Or the Mac Pro just gives you the hard "shut down" as a safety measure.

I advise to either go for an external PSU, which you would have to hook up to internal power to make it switch on / switch of with Mac Pro.

Or, to get it to run safely with internal power, do it like this:

1. Get a 2 x 6 pin to 1 x 8 pin adapter to give the 8 pin port on the card the requires 150 Watts.

2 . Get a 2 x SATA two 1 x 6 pin adapter and connect to 2 SATA ports on the board. Gives you the 75 Watts for the 6 pin easily.

That way you'll lose two SATA Ports, but you still have 4 in total for drives (Two Bays and 2 from the optical bay).

Enough power, no danger for motherboard. No external PSU needed.

A lot of threads I see, people specifically look for a reference card that only uses two 6-pin aux power cables also.

Those 2600's - install for emergency but otherwise keep it out, it could also affect your testing and ability unless.you.need early boot screen to debug and troubleshoot.\

Built a low cost $800 (sans GPU, SSD/HDD) PC wtih PCIe 3.0 and 8 x SATA III ports is a whole lot easier and then using a PSU with 2 x 8-pin and 2 x 6-pin that meets your needs. I like Asus but some like other boards for various reasons.

Hi nfoo, The card came with a 8 pin that splits to two 6 pin cable see pic. It also came with a duel molex to six pin cable.

So maybe I could use the duel molexs from the DVD bay and put that in the six pin input on the card.

And take the 8 to duel six pin and plug that into the two motherboard six pins inputs?

Do you think that would give it enough power.