Why mac pro 2013 not supporting illustrator GPU rendering

Question

Here, all nvidia cards supporting this:
http://helpx.adobe.com/illustrator/kb/gpu-performance-preview-improvements.html
now I'm thinking, that buying the new mac pro 2013 maybe wasn't the best idea... Apple put in AMD GPu's, that is fine by me, but come on, give us some more support for them! Normal windows PC (for 800€) with nvidia GPU is faster at rendering in Illustrator, than my workstation mac (3500+€)! Really? O.o
And story doesn't end here. I was reading one article about GPU usage in this new mac pro and then I tested it myself. Only one GPU is used and the other is barely touched! And this goes for Maya, photoshop, illustrator and other adobe programs. I was shocked, that I discovered I have one GPU to warm up my room and only one actually doing all the work.
Ok I understand, that also software developers needs to support stuff and write their software to actually use GPU's, but adobe creative suite is one of examples, where software is actually capable of using GPU via openCL and in some cases even CUDA from nvidia.
And there is one more thing: new mac pro, has 2 identical AMD GPU's inside, which can work in crossfire configuration under windows in bootcamp, but not in OS X. Sometimes I even play some games on my mac and sometimes I'm testing them (I'm artist, but I also like to develop and test some games in my free time) and it's kinda a shame, that I can run games with better performance under windows in bootcamp.
When I bought this computer I thought this is going to rock and sweep up with all my previous machines. Well in practice it is much of unused potential and great room warmer. It's kinda sad, that on my girlfriend's PC I can play games with better frames and details on GF 660GTX than on my mac pro... I know I know, mac's aren't for gaming, but hey, sometimes it is good to get my mind on rest and blow up some enemies!
I'm not saying mac pro isn't great product, which is (very great). But support to use all computer capabilities is very limited and Apple should kick developers in their back side and push them to start developing things to use GPU's more.
I'm also not expecting Apple to jump on their feet and fix problems overnight. No, just start thinking of adding more support and things that would make our computers much more used and not only good decoration on desk. First would be a good steep adding crossfire support to OS X. That might even help at rendering some 3D scenes?
Next step would probably be better cooperation with software developers, like Adobe , Autodesk,... If adobe made good support for GPU rendering in Illustrator, aim that we get that support soon as well. I'm sometimes having a lot of paths and objects and rendering goes pretty slow then.
I'm also thinking about that AMD choice Apple made wasn't so good when you see that Nvidia puts much more effort into supporting more and more stuff, while AMD is sitting idle not even updating their drivers anymore.
Oh and one more thing: Can we please, please, please, please, preeeeeetty please get 10-bit output support on OS X? It's kinda sad, having good mac workstation with 10-bit capable monitor (dell UP2414Q) and no support for it, while other PC workstations all support it... Photoshop is working much better on OS X and here I have much better integration and everything and I really love working in Photoshop running on OS X, but some basic things are missing and I'm really asking myself sometimes: was that good decision? Photoshop was first written for macs and in 2014 there is much better support for adobe software on windows than on OS X. Where went wrong?
Don't take me wrong and think I'm just ranting here without any good reason, but think: buying very expensive computer that is supposed to make creative work easy and painless is actually just on paper. In reality computer potential is pretty much unused and that makes me thinking if I would be much better buying iMac instead of mac pro...
TL;DR: I wish for some more support from Apple for their new expensive mac pro's 2013. They are great piece of equipment, but equivalent PC's running windows are surpassing them in this department, specially when GPU's are involved. Now I would like to point this out to Apple, so I don't know where to write so they will read so I first wrote that here. I hope someone from Apple reads this and give us some feedback on those missing things or maybe I get direction where to write to Apple so I get maybe some response from them(?):
-not enough GPU support for creative software (adobe suite, autodesk,...) - nvidia + windows offering much more for less money?
-no crossfire support on OS X. Any particular reason for that?
-no 10-bit support for 10-bit displays. Why not? Hardware is capable, why software isn't?
-lack of openCL software out there. Apple isn't doing much to get more support or developers just too lazy to put more effort into this? GPGPU isn't the future as some companies are trying to convince us?

Answer 1

Grant Bennet-Alder wrote:
All displays are supported by one GPU -- the display GPU. The second GPU is reserved for un-interrupted GPU computing and has no Display output Hardware.
Anandtech has a discussion of this in his review of the late 2013 Mac Pro.
Under OS X the situation is a bit more complicated. There is no system-wide CrossFire X equivalent that will automatically split up rendering tasks across both GPUs.
By default, one GPU is setup for display duties while the other is used exclusively for GPU compute workloads. GPUs are notoriously bad at context switching, which can severely limit compute performance if the GPU also has to deal with the rendering workloads associated with display in a modern OS. NVIDIA sought to address a similar problem with their Maximus technology, combining Quadro and Tesla cards into a single system for display and compute.
from section 9:
http://www.anandtech.com/show/7603/mac-pro-review-late-2013/9
Another problem here: on windows bootcamp crossfire IS working, but not in OS X. As I wrote, sometimes it would be better to get more rendering power than computing power (actually at current state of GPU computing software, computing GPU isn't working very much if at all). It would be nice to have an option to switch on and off crossfire so we could use more rendering power when needed.
Also not all people are doing video rendering on their computers. What about 3D modelling and 2D work in photosohp? And maybe people like me are occasionally wish to play some games on their mac?
You linked me GPU usage from one program (probably adobe after effects or premiere pro or apple final cut X?), that is probably one of the only pieces of software that actually uses both GPU's under OS X. I made same experiment with software I use and I even tested some software I don't use but it is advertised it is "optimized" for mac pro like pixelmator.
And guess what? Second GPU is 99% time idle. Even when some stuff is using openCL in Photoshop, stuff is still computed on rendering GPU and not on computing one, which makes computing GPU just a good room warmer as I wrote before. Wouldn't be better to at least use second GPU for something than heating air?