Cmer

On March 4, 2016 at 3:27 AM, cyphersk8 said:

@goalque thanks so much for the script and support you provide. I've scoured these posts and with your help I've managed to get the 980Ti/Akitio combo running while leaving the native 5k alone. That line 62 trick works great. I do have a few small questions and/or problems that I hope you can help me to address:

 

ALBUM OF IMAGES: http://imgur.com/a/byL6W

 

1) If don't disable the eGPU secondary monitor output (using the line 62 trick) I get very weird resolutions on the 5k. When I first boot up, only the center of the monitor is displayed. It looks like how it is when you display vertical video on a widescreen device. If I click 'sleep' before logging in, and then wake it back up, the entire screen fills out but everything gets huge. It's like it thought it was 5k, then HD. I can never get it to look or feel like the native 5k afterwards.

 

2) For gaming, starcraft 2 doesn't recognize the 980Ti unless I am utilizing the secondary monitor set up as my 'primary' through SystemPrefs/Displays. When I do that, I can run the game in windowed mode and drag it back to my 5k, however, I get horrible fps. It's really bad. Any ideas on how I can use the 980Ti for gaming on the 5k? I don't own a dedicated secondary display. I've been using my TV for testing purposes.

 

3) The big problem. My PSU (Corsair CX750M) makes some very interesting noises when the eGPU is under load. I'm not sure how to describe it, but it sounds like very fast ticking noises, definitely from inside the PSU chassis. It happens if I run the secondary monitor with starcraft 2 open, but it also happens when I've disabled the eGPU output and only use the eGPU for rendering support. It sputters and changes pitch depending on how intense the load is at the moment. Ever run into this before? I doubt 750w is too little power for such a setup. Attached audio clip of PSU noise.

 

 A little about my set up:

 

Computer Hardware:

• iMac (Retina 5K, 27-inch, Late 2014) 
• 4 GHz Intel Core i7
• 32 GB 1600 MHz DDR3
• AMD Radeon R9 M295X 4096 MB
• Yosemite 10.10.5

 

eGPU Hardware:

• EVGA NVidia GEFORCE GTX 980Ti
• Akitio Thunder2 Pcie
• Corsair CX750M PSU

 

 

Setup is as follows: Akitio board removed and mounted to a custom wood base (I didn't want to destroy the factory case). 980Ti installed directly to the pcie on the akitio board. PSU directly powered by a ups (120v output with almost no load). The PSU came with cabling that I used to power both the 980Ti and the Akitio board. The 980Ti is powered via an 8pin connection on the back of the PSU to a 6-pin and 6-pin+2-pin on the 980Ti. (the cable has two 6-pin connectors and two 2-pin connectors attached at the end, but attaches at the PSU by a single 8-pin). The Akitio is powered by a 6-pin connection at the PSU that had 3 molex connectors on the end. There are 2 molex connectors attached that run to a single 12v DC Barrel plug. All connections securely soldered, heatshrinked, and appear solid. 

 

For testing the noise, I can either run a secondary monitor under load or run my single 5k and use the GPU accelerated nodes inside of a program called Nuke. Changing the focus of an image, for example, causes the PSU to make noise when sliding the values around because it is GPU accelerated. 

 

Thanks for the help in advance. Truly appreciative of what you've done here. 

 

psu_noise.m4a.zip

On March 4, 2016 at 3:27 AM, cyphersk8 said:

thanks

I have the same Mac as you and same enclosure. I have 2 graphics card I tried: GTX 970 and GT 640, but give me the resolution issue you're also experiencing. 

Hopefully we can find a fix!