Sidebar Sidebar
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

What don't I understand?

J

jpine

macrumors 6502
Original poster
Jun 15, 2007
393
71
Ok, guys. Help me understand what's going on here. I bought a used 5,1 with a flashed 7970 (3GB) and 64GB of RAM that I intend to use with the Oculus Rift. This rig is for research and not for developing commercial apps. Just for fun, I compared the OpenGL capabilities (I don't care about OpenCL) of the MacPro rig to that of a brand new i5 iMac with the basic 1GB mobile GPU. I expected the MacPro to squash the iMac. As you can see from the screen shots of the Valley OpenGL test, that did not happen.

One other thing: The 7970 was not flashed by Macvidcards, so I assume the wattage of the card is stock. Does this card run too hot for the MP to safely handle? I'm open for suggestions for a better GPU that does not require an EPS. I do have a 2.5GB GTX 570 that was flashed by MVC laying around so I'll test the MP with it and see if the results change any.

BTW, the resolution for the test was 1280x720. That is the resolution for the Oculus Rift.

TIA!

JP
 

Attachments

  • 12 Core.png
    12 Core.png
    64.1 KB · Views: 127
  • iMac.png
    iMac.png
    65.5 KB · Views: 92
h9826790

h9826790

macrumors P6
Apr 3, 2014
16,614
8,546
Hong Kong
I just ran that test with my 7950 (OC to 850MHz), and get almost identical result as yours. Even though I think the 7970 can do a little bit better than that, but should not be too much.
 
Last edited:
666sheep

666sheep

macrumors 68040
Dec 7, 2009
3,686
291
Poland
Double minimum FPS could be considered as "squash".

What you're missing is the fact that Unigine scores are CPU clock/single thread performance dependent.
Resolution matters as well. Difference would be bigger in higher res.
 
J

jpine

macrumors 6502
Original poster
Jun 15, 2007
393
71
mikeboss said:
maybe the 7970 isn't properly modded and the PCIe Link Speed is running at only 2.5 GT/s instead of 5.0 GT/s.
Click to expand...

Link speed is part of the modding process under OSX? I thought that was an issue pertaining to Windows under Bootcamp.
 
h9826790

h9826790

macrumors P6
Apr 3, 2014
16,614
8,546
Hong Kong
Yesterday, I ran the test when remote controlling the computer, it seems the result is not very accurate.

So, I just did it again. This time I was sitting in from of the computer, no active remote control section. The computer still running as a server, have few background tasks, and not intentionally optimise to run the benchmark.

And this time, I have a better result.
Screen Shot 2014-09-21 at 4.19.28.jpg
(This was using the basic preset. I don't know why it says custom with medium quality.)

I expect a 7970 can do better than this. So, there may be something wrong in your system. Or as 666sheep said, your score was limited by something else (e.g. your single core performance).
 
N19h7m4r3

N19h7m4r3

macrumors 65816
Dec 15, 2012
1,191
8
At the resolution you're running the tests at your CPU is taking the lime light. Crank it put to the extreme setting to single out the GPU more.

Also note that AMD's OpenGL drivers have always been behind NVIDIA's, and NV has always held the lead in the OpenGL performance.
 
J

jpine

macrumors 6502
Original poster
Jun 15, 2007
393
71
mikeboss said:
nope. you need to do this modification on the card itself ->
https://forums.macrumors.com/showthread.php?p=17183586

did you check in the System Profiler if the link speed is 2.5 or 5.0 GT/s?
Click to expand...

Thanks!!! When the previous owner flashed the card, he didn't remove the resistor. The card is indeed running at 2.5 GT/s. The bad news is that there is no way in hell I'm risking turning this card into a paper weight by trying to remove the resistor myself. I think I'll just put it on eBay or here on the forum and use the money to buy a MacVidCard.

Thanks guys!!!!!
 
Last edited:
J

jpine

macrumors 6502
Original poster
Jun 15, 2007
393
71
Well, I went ahead and popped the R17 resistor off the 7970 and am now running at 5GT/s. At 720P, it makes no difference. The difference is noticeable if I crank up the res setting in Valley. The "min" fps is doubled running at 5GT/s.
 

Attachments

  • Screen Shot 2014-09-25 at 12.12.22 PM.png
    Screen Shot 2014-09-25 at 12.12.22 PM.png
    62 KB · Views: 62
666sheep

666sheep

macrumors 68040
Dec 7, 2009
3,686
291
Poland
If you care about Unigine scores, you gotta get highest clocked CPUs and overclock your GPU. That way 7950 can beat stock clocked 7970s easily.
But it's only a benchmark ;)
 

Attachments

  • Screen Shot 2014-09-22 at 18.22.36.png
    Screen Shot 2014-09-22 at 18.22.36.png
    58.7 KB · Views: 70
You must log in or register to reply here.
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.
Top Bottom