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Looking for clarification: can a 4,1 run an AMD R9 280x without external PSU?

Sharky II

Sharky II

macrumors 6502a
Original poster
Jan 6, 2004
979
357
United Kingdom
Hi,

I'm looking for a new graphics card and would like to be 100% clear on if my 2009 Mac Pro can run an AMD R9 280x without needing an extneral PSU? I'm reading that some people can, and some people can't. Here's one thread where somebody mentioned that they can't get it going without external power: https://forums.macrumors.com/threads/1722681/

My system is relatively loaded for a single-CPU:

2009 4,1 flashed to 5,1 with W3690 3.46GHz 6-core chip, 24GB 1333 Ram, 4HDs and an SSD in the optical bay. SSL MadiXtreme PCIe card in there too.

Currently have a GT120 which i'd consider leaving in another slot in case i need to boot 10.6. If i have to remove it, that's OK, i'll just swap cards as it won't be that often. I'd like to be able to add an Apricorn Velocity Duo in the future, as well as another SSD and possibly a USB3 or other PCIe card.

I was leaning towards: MSI AMD Radeon R9 280X GAMING 3GB. I won't actually be playing games on it, and have no interest in over-clocking it unless it suddenly becomes underpowered in the future. I'm just looking for a modern GPU to handle my 30" and 24" display, speed up the sluggish GUI, speed up FCPX for the rare occasions its used, and also handle 4k displays when they're cheaper.

I understand that you have to use one 6-pin cable and one 6 -> 8 pin converter cable. Is this a problem?

What do you guys think?

If it does require a PSU, i'll just get a 7950, or perhaps a 7970 - they're all roughly the same price on eBay. I need as quiet a machine as possible.

Thanks!

Ed
 
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See... this is why i'm asking!

Right... so you can get 75 watt from PCIe, then 75 watt from each 6-pin cable... is that correct?

If so that's 225W, which means that under certain conditions, there could be issues...?

I'm not a graphics power user, i'm an audio guy that likes big monitors (4k soon), smooth guis, and does some occasional FCPX work. I don't want to push things unnecessarily.

Thanks!
 
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No power issues, believe me. I used a lot of 8-pin cards in my MP (including 280X first rev - more power hungry than rev 2), some nearly 260W under heavy load. Heavy means ~100% GPU load.
Kennyman first wanted do overclock his card, next he was planning to add second one.
 
666sheep said:
No power issues, believe me. I used a lot of 8-pin cards in my MP (including 280X first rev - more power hungry than rev 2), some nearly 260W under heavy load. Heavy means ~100% GPU load.
Kennyman first wanted do overclock his card, next he was planning to add second one.
Click to expand...
In that case, R9 280x might be the next upgrade in my 5,1 :cool:
 
666sheep said:
No power issues, believe me. I used a lot of 8-pin cards in my MP (including 280X first rev - more power hungry than rev 2), some nearly 260W under heavy load. Heavy means ~100% GPU load.
Click to expand...
+1, can confirm that based on practical experience. I'm using a Gigabyte 280X BF4 LE flashed with EFI in my 2009 cMP 5,1 and it works like a charm, no issues either.

Hardware Monitor shows the classic Mac Pro is built with lots of 'headroom' regarding power draw.
 
That's great, cheers guys.

My hesitation was based on Kennyman's comment in that thread:

"Just want to update this post, I can confirmed that 280X works well in Mac Pro 5,1. But I could not run the card at factory clock using the internal pcie power."
 
Feel free to believe him or us, I'd say thats spreading FUD. There aren’t any reports about real world apps causing a shutdown, nowhere. Have yet to see a real proof of the same or a comparable config that caused any harm to a 4,1 or 5,1 motherboard either.

Stay away from that ported Furmark crap, thats a bad habit of windows users anyways :p and you’ll be fine.
 
Sharky II said:
That's great, cheers guys.

My hesitation was based on Kennyman's comment in that thread:

"Just want to update this post, I can confirmed that 280X works well in Mac Pro 5,1. But I could not run the card at factory clock using the internal pcie power."
Click to expand...

Hello,

Did you bother to read my wrong thread or just a sentence? If it is only one sentence…then please, no need to quote my post.
 
Fangio said:
Stay away from that ported Furmark crap, thats a bad habit of windows users anyways :p and you’ll be fine.
Click to expand...

Even "ported Furmark crap" didn't bring my MP's PSU to overload. With GTX 580 SSC it was close, ~275W peak. It was playing with fire ;) 280X is a lot safer.
 
Hi,

I did read your thread, but I dont know anything about overclocking and had a few reservations. I didn't fully understand everything said.

Your thread was just one example that I'd read that made me unsure - there are plenty of other threads saying that there's not enough power, and that somehow the 6->8 pin thing was a bad idea. Hence this thread. No need for any animosity.

Cheers,

Ed
 
Sharky II said:
Hi,

I did read it, but I dont know anything about overclocking and had a few reservations.

Your thread was just one example that I'd read that made me unsure - there are plenty of other threads saying that there's not enough power, and that somehow the 6->8 pin thing was a bad idea. Hence this thread.

Cheers,

Ed
Click to expand...

ok, then please ignore my post and follow the rest.
 
On a slightly unrelated note - but while i have you guys here :D - how can i tell if the 280x is the Rev 2 that runs cooler?

Is it across all 280x boards or just specific vendors? As i said, i'm after the MSI Gaming.

I'm trying to google to find out about it, but nothing's coming up immediately.

Cheers

Ed
 
First rev was based on Tahiti XT2 chip, second one on XTL. If you'll buy brand new, not the aftermarket one 99,99% that you'll get the second rev.
 
Right, so there's no way of telling if you are getting a 1.2 other than the BIOS. I thought there might be some visual differences - i was planning on getting a second hand one off ebay.

It might be worth spending the extra for a new one then.

Thanks for all the info!

Ed
 
I've been running a flashed 280X in my 5,1 Mac Pro for a couple months now without any power problems. But I have to tell you that I've been disappointed with it's capabilities. It's barely better than my old GTX 680 when it comes to rendering & exporting within Adobe Premiere Pro & Media Encoder. This is why I'm planning on upgrading to the 290X next week once Yosemite drops. As far as whether or not the 290X can be safely powered by my Mac Pro, well I guess I'll see.
 
I'm sure coming from a GT120 (8800GT on previous mac) it will good enough for me :D:p

Plus, as an occasional FCPX user, i like how it's basically a D700, and so i know it'll be pretty well optimised for.
 
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