AMD Radeon & NVIDIA Quadro graphics cards together

I recently purchased a Radeon Vega 56 graphics card to go in my PC. I already have a a Quadro M2000, which is good in that it does 10 bit OpenGL (i.e. Photoshop can use it for 10 bit output), but it isn't very good for running modern games. So I purchased the Radeon card for that purpose, and it should also work well for other tasks with its 8GB of HBM2 memory.

Before I purchased the card I spent quite a while researching if the two cards could be used together. There seemed to be various conflicting information. From what I read, it seems that with NVIDIA cards you used to be able to run a Geforce and a Quadro at the same time, but that is no longer possible. It also seems that running a Radeon and Radeon Pro in the same system is not possible. Running a Radeon and a Quadro seemed possible, so long as both are not in use at the same time.

The advice seemed to be to set up dual boot - one OS that has drivers for the Pro card while the non-pro card is disabled. Then another OS for the non-pro card, with the Pro card disabled.

Well, I installed the Radeon in my system, and it seems to work okay without any messing - I can have one monitor in my Quadro, one in the Radeon, and no crashes or anything. The card performance does seem rather limited and I did get crashing when I tried undervolting it. But I suspect this is down to silicon lottery / useless reference cooler rather than any driver clashes.

Something I haven't tried yet is connecting both cards to my main monitor (so I can switch input on the monitor to switch between which card the monitor is running off), but I can't see there being any issues.

Of course, I can't say that all Radeon cards work okay with all Quadros, but at least in my experience it works okay for the two cards I have on my system.

Alesis Multimix 16 USB 2.0 crackling over ASIO4All

I recently purchased an Alesis Multimix 16 USB 2.0 mixer, while this is quite an old and outdated mixer it has the benefit that it can send all 16 channels separately over USB to your PC (rather than just the mix like most modern mixers). In Ableton if you select ASIO as the audio driver type then you can only select 1 device, which is used for both input and output (as far as I know). But this isn't what I want - I want 16 channels in from the mixer, then audio out to my speakers, not back to the mixer.

So to get round this limitation I use ASIO4All. In ASIO4All I select the multimix as an input device, and my speakers as the output. In Ableton I then select ASIO4All as the ASIO device to use.

I was testing the multimix with a microphone input, and found that when I was talking into it there would be occasional crackling. Plugging headphones into the multimix there was no crackling. If I set ableton to use the multimix as the ASIO device, then there was no crackling (but getting the multimix to output only the signal received via USB is a right pain and latency was terrible).

I messed around with the buffer settings quite a bit, but it didn't seem to make any difference at all. Eventually I tried a different USB cable and USB port (one of the recommendations online was making sure you don't have it plugged in a USB hub, but straight into your PC). Amazingly this actually fixed the problem. The original USB cable works fine, but it seems the issue only occurs when plugged into the rear USB ports on my PC. Plugged into a USB (3) hub I get no issues at all.

What's especially strange about this is that whenever I have had issues with USB devices before, it has always been that they need to be plugged into a rear USB port, and that plugging into a front port or hub is the problem. But with the multimix it seems the issue is reversed.