Poor GPU performance with 3,1

[tpivette89]

I have a cMP 3,1 with a HD Radeon 7970 GPU. CPUs are a pair of X5272s (2-core at 3.4ghz), RAM is 16GB at 800mhz (8 x 2GB). Running 10.11.6 on a SSD using one of the SATA II drive bays. For monitors, I'm running a pair of ACD 23" aluminum versions.

Running Unigine Valley on high settings (not Ultra), I'm only averaging around 27fps. With the same card on my 4,1 (flashed to 5,1) I get an average framerate of 50fps... however, that is a 12 core machine with more RAM (24GB).

What is keeping the GPU from reaching the performance figures I know its capable of? Is there something I'm missing or lacking?

 

[Ludacrisvp]

I find it interesting you are running dual dual core processors in the 3,1 ... curious why you have that config. Was it just to get 3.4 GHz vs 3.2?

Anyways for the GPU it is probably because the 3,1 isn’t running the GPU with PCIe 2.0 x16 and is probably doing 1.1 or 1.0.

 

[tpivette89]

I find it interesting you are running dual dual core processors in the 3,1 ... curious why you have that config. Was it just to get 3.4 GHz vs 3.2?

Anyways for the GPU it is probably because the 3,1 isn’t running the GPU with PCIe 2.0 x16 and is probably doing 1.1 or 1.0.

I just wanted to see if these CPUs worked in the 3,1 Mac Pro (originally when I got the machine, they were not included on the compatible list). Plus, yes, I wanted the better single core scores... but now realize that the difference between the 3.4 vs the 3.2 in single score is basically negligible.

Why would it not run PCIe 2.0? Is this something that has only happened recently due to the new 138 firmware? Or is it a limitation of the 3,1?

 

[orph]

it's cpu speed & drivers, netkas did a bunch of posts on it
http://netkas.org/?cat=12
that was from a quick look, he looked in to it a lot.

has nothing to do with PCI speed

 

[Fl0r!an]

Ther's a known power management bug when running GCN GPUs in a 3,1. A workaround is trashing AppleIntelCPUPowerManagement kexts. There's more information on this topic here and on netkas.org.

Additionally, the GPU will be CPU-bound due to quite slow single core performance of those CPUs.

 

[tigerintank]

Is this something that has only happened recently due to the new 138 firmware? Or is it a limitation of the 3,1?

Is there a new firmware for the MP 3,1? Can someone point me to some info pls

 

[tsialex]

Is there a new firmware for the MP 3,1? Can someone point me to some info pls

No, only for MP5,1 and MP6,1. MP3,1 is unsupported since El Capitan.

 

[tigerintank]

No, only for MP5,1 and MP6,1. MP3,1 is unsupported since El Capitan.

ok thank you