Maybe also of interest for you driver stability and performance.

http://www.tonstudio-forum.de/blog/inde … cks-de-en/

Ahh I just read that link, i don't think you realise ramses, my imac is only usb 2, 2 usb2 busses on four ports, that i have turned into 22 ports with powered hubs.. This is why i said there's just not enough bandwidth for a high channel usb interface left.
The next model after mine got usb3, which obviously would have worked well with the RME.

IF i got a thunderbolt hub, like the OWC, it has 4 usb 3 ports.. and of course would be running on the thunderbolt bus not the usb bus already existing, then it would probably work great.... My mac has thunderbolt 1.. i believe it has it's advantages.. with thunderbolt 2, it's 20gb shared over one bus and 2 port.. With TB1, i have actually 2 independent thunderbolt busses in my imac with 10gb/s each. Yes unlike TB2 i can't get 20 from one port, but i've had nothing but success and it also means i can chain a couple hard drives (WD raptor with thunderbolt through then SSD at end of chain) to max out most of one bus, and leave the other entirely free for audio.

I love this imac as it makes no noise and just works, i will keep repairing it if anything happens till the point it's unsalvageable lol.

Oh I can assure you i don't have anything against any protocol, i only judge things for my own situation. And look, if i get a new imac pro one day, or mac pro, i can then use the usb of the ufx i will buy anyway. I tried to haggle them down a bit today as they have had those 3 for ages, and see what their decision is tomorrow.

I have to also stay on my imac cause i love yosemite and pro tools 12 works the best on it.. and i will be forced to high sierra once the new macs are out... I also have a lot of old gear with drivers that stop at yosemite.
El capitan was a disaster for me, and sierra which is on my laptop, is ok, but PT still the best on 10.10.5. Weird glitches in sierra and things getting 'stuck', still, 1000x better than el capitan.
I am the type that likes to use what works. Believe me, i refused to move on from logic 9.1.8 and snow leopard for a long, long time (till yosemite came out)..mainly because of snow leopard which i STILL love.. such a lean fast OS.. 
I only left logic after 20 years cause i started heavily using uad plugins to mix,  and logic's ADC does not correct automation for ANY plugin, even zero latency ones, when one is using latent plugins in the same signal path, i.e automation is always out by the time of the total latency of the latent plugins, so needs to be manually adjusted every single time you remove or change even a single UAD plugin! It was just too much after a while and I was sick of it...

Pro tools fixes all that completely, and now I am used to it like i have been using it forever.. If i wasn't using so many plugins with latency, i would have stayed on logicX but had to leave 2 years back, I still check every release out of curiosity but it's never fixed. I've reported it to apple 20 times LOL. I gave up as they obviously don't care.

I do need to ask one more question..

pro tools vanilla does not have a core audio recording negative/positive offset in audio settings like all other DAWs..can someone confirm to me that the RME ufx driver accurately reports the latency to PT, *including* the converter latency? I can test it during a loop back recording but too expensive to spend 2 grand to test lol.
Cheers -PS i think i'll get a S/H eleven rack for $300, problem solved by losing apollo for guitars, and it has aes/ebu out, so there is a perfect use for the UFX aes/ebu input

> the RME ufx driver accurately reports the latency to PT, *including* the converter latency?

Under Mac no driver talks to an app. Our driver exposes the latency values including analog I/O to Core Audio. What ProTools then does with that information is not under our control.