MP 1,1-5,1 Mac Pro 5,1 Vega 56 fan always on idle...

[TKOS7]

Hi,

Recently purchase a Mac Pro 5,1 from FB marketplace. After a clean it works great. Its a dual 2.4ghz CPU version, and I plan to do some upgrades.

I bought a GTX680 and that worked a treat, but didn't give me the GPU performance I needed to run the games I would like. I've just swapped it out for an MSI Vega 56, and while the GPU works fine, it seems to be running quite hot (50* on idle), and while the Mac Pro PCIE fan does speed up according to the load, it seems the actual fan on the GPU is just idling no matter what temperature the card gets to, and I feel like that can't be right. This didn't happen on the GTX680.

Any help with this? I'm not running Opencore, just stock Mojave 10.14.6.

Thanks

 

[h9826790]

Hi,

Recently purchase a Mac Pro 5,1 from FB marketplace. After a clean it works great. Its a dual 2.4ghz CPU version, and I plan to do some upgrades.

I bought a GTX680 and that worked a treat, but didn't give me the GPU performance I needed to run the games I would like. I've just swapped it out for an MSI Vega 56, and while the GPU works fine, it seems to be running quite hot (50* on idle), and while the Mac Pro PCIE fan does speed up according to the load, it seems the actual fan on the GPU is just idling no matter what temperature the card gets to, and I feel like that can't be right. This didn't happen on the GTX680.

Any help with this? I'm not running Opencore, just stock Mojave 10.14.6.

Thanks

50°C idle is cool for modern GPU. They are decided to run at the "target temperature", but not as low as possible. The target temperature usually between 75°C to 85°C. Below that temperature, the onboard fan usually run at idle speed, or even stop spinning.

The cMP PCIe fan isn't just spin up according to the GPU temperature, but also the power draw. Which somehow make sense, because when the Aux / PCIe power draw is high, then something will warm up and need more cooling. Therefore, the SMC also sense the power draw and spin up the PCIe fan accordingly. Which means, that fan spin up not necessary because the system sense that your GPU is too hot, and want to cool it down.

Also, the temperature of Vega is the junction temperature, but the GTX680 reports the edge temperature. They are from different source, the junction temperature is the hottest spot on the GPU, it can easily 10-20°C higher than the edge temperature. Therefore, you can't just compare the GTX680's idle temperature to the Vega's idle temperature.

For Vega, it can run at 115°C without any trouble. But the GTX680, you should keep it below 100°C.

Anyway, from your description, everything is working correctly, nothing to worry about.

 

[TKOS7]

My dude, thanks very much. Really appreciate the in depth reply. Have a great day.

 

[Lasthenia]

Curious... did you do the Pixlas mod to adequately power the MSI Vega 56?

The MSI Vega 56 requires 2 x 8-pin power connectors.

 

[TKOS7]

Yo - the vega 56 from what I've read doesn't need the pixlas mod, just needs 2x 8pins which I have.