Mac Pro 2008 video issues with Gigabyte RX460

[nobail]

Hi Folks,

First off, I am not a mac expert, so thanks in advance for any advice.

I was recently given an Early 2008 Mac Pro and I decided to put some money into it because.. well.. free Mac and decided this would be a nice entrance into the world of Macs and video editing. So, bumped the CPU's up to dual 3.2ghz Xeons. Then, I bumped up the memory from 16Gb to 64GB (even though only 32GB is officially supported, but according the interwebs, 64gb works), I put in an OWC PCI Sata adapter to use with a Samsung EVO SSD that I already had. I also bumped up the OSS to Sierra 10.12.4 and installed a Gigabyte RX460 as that video card seems to be the best out of the box solution for Sierra and I wanted to do some gaming, but nothing extravagant. Anyway, it would seem with this configuration this Mac Pro is pretty much as good as it is ever going to get.

So, my problem is with playing video and I have not even tried gaming yet. With the RX460 installed, video just plain sucks. When I play HD video, the playback is choppy and horrible. When, i pull out the RX460 and put back in the stock ATI Radeon HD 2600 XT 256 MB card, the video is much better. It's not great, but certainly watchable. What am I doing wrong? Well, other than running an unsupported OS, more memory than is supported and a non-stock video card? However, according to my research, all of these "should" work, but perhaps I am missing something.

Any advice would be appreciated.

Regards
-Hal

 

[CapnDavey]

I think I read it somewhere that some models of those RX cards had issues I think there is a fix for it.As far as the OS goes plenty of people running 10.12 on a 3,1 with no issues I guess you used dosdude's patch?

 

[nobail]

Yep, I used dosdudes Sierra Patch Tool and then applied updates to 10.12.4.

 

[nobail]

So.... maybe this is resolved, but I will play around more. So, the old ATI card only had dual DVI out, I was using DVI out on the RX 460 as i was too lazy to change cables. However, I have since switched to HDMI, and all seems working well. I'll play with it some more and mark this as resolved it it seems ok. Does it make sense that DVI out would have issues but HDMI (and maybe display port - but I can't test that) could be ok?