> All slots on my motherboard are now occupied with the UFX III

How that, UFX III is no PCIe card. Do you mean perhaps USB ports? But how can all be occupied by the UFX III, it only needs one USB3 port.

Can you please be more specific. What mainboard are you using and what do you mean?

> I would like to buy a USB-C expansion card.
> I heard here that the Sonnettech cards are good, but also expensive at over €200. Is it worth it?

Why an USB-C expansion card? UFX III has no USB-C ports. Yes I know, you can use a special cable for that, but ...
Although you might have luck with e.g. newer ASMEDIA USB3 chipsets (the older ones used to have issues)
I would strongly recommend taking a card with a chipset that is known to work.
Then it would be best to isolate the UFX III behind such an expansion card and wouldn't connect any other device to it.

If you heard something about expensive cards, then it were special 4-port cards with 4 dedicated USB3 controller per port.
Such cards were expensive because each of the 4 cards had a dedicated USB3 controller and by this the full speed, therefore they needed a PCIe socket with 4 PCIe lanes to the the required total Bandwidth of around 20 Mbps (4x5) in total.

But such an expensive Sonnet card with 4x FL1100 chip is not available anymore.

Simply take the available card with FL1100 controller which is shared between the 4 ports.
Therefore I would not connected any other device to it, only the UFX III.

This is the card: https://www.sonnettech.com/product/alle … 4port.html

Windows 10 and 11 have already the required driver and it uses already the more efficient MSI (message singalled interrupts).

I recommend you to take Lindy Premium cables, according to the standard they may be 3m long, not more.
If you need longer cables, then get the active extension from Startech.
More information on that see this thread:
https://forum.rme-audio.de/viewtopic.ph … 77#p207877

> Are the USB cards stealing my graphics card's lanes?

How should anybody be able to tell you, if you do not even tell, which mainboard you have?
Usually you get such information about PCIe sockets with shared PCIe lanes from your mainboards manual.

Found this information in an older thread, but also there you are not specific enough, as there are different models of Gigabyte Z390 Aorus ... Elite, Master, Pro, Extreme, Ultra ..

Please put such fundamental support info into Forum signature or write it explicitely into new threads.

Nobody has really fun to lookup such fundamental support information in older threads to finally find out that it is still not really complete.

Maybe this reddit thread might help you, but I am not 100% sure, whether this information is applicable for all those different model variants. The better source of information might be still the mainboard manual.
And as you can see the lanes are not only shared between PCIe slots but also between Sata Ports and NVMe sockets in the board if I understood correctly. You need to take some time, to find this out.

https://www.reddit.com/r/intel/comments … and_lanes/

Tools like CPU-Z (or GPU-Z?) show you, whether your GPU runs are x16 or x8. Try different PCIe slots for the card if needed.

Thanks.

I would disconnect all devices and try only with Mouse, Keyboard and UFX III.
Then you have several USB-C and USB Type-A ports to check, whether the UFX III runs perhaps on one of those without any audio issues. While testing keep the driver settings window open and watch whether there are any CRC errors increasing.
Only "Zero" CRC errors are acceptable.

If you find such ports, make a note.
Then connect the other devices one by one while still checking for audio drops and CRC transport errors.

This way you find out
- whether there is an USB port working fine for you or
- maybe even what additionally connected USB devices are causing issues.

If this all does not lead to satisfactory results, then get the Sonnet card, you have plenty PCIe sockets for testing
a) which PCIe socket you can use safely without loosing PCIe lanes for your graphic card
b) checking how it all works with the UFX III isolated alone behind the above mentioned Sonnect card with FL1100 chips which were tested / validated to be ok by RME, see manual (I think it was around ch 40.2 ...).

Great, thanks already once!
I think it's the number of devices.

I am now even thinking about buying a new motherboard.
A Z790, since I wanted to update my CPU anyway times.
Would you have recommendations?

Edit: I have tried to replace the original USB-C cable with the original USB 3 cable. Unfortunately, unsuccessfully.
       The latest drivers are also on it. I wonder about 0.9827. Are we still in the beta?

It is now ordered, the card.
I will report.

> Intel CPU does not have higher IPC than AMD

Really sure? I read it last recently but have no further references URLs.

> AMD may have some latency due to chiplet architecture, but one may use APU that does not have chiplet architeture.

Which one do you mean? I thought the more interesting / performant ones would have all the chiplet design.

> And Intel big-little introduces massive, massive latencies if OS moves thread from big core to small and vice versa.

The question is, whether this is always the case or whether it could be solved. Bitsums Process Lasso Pro seems to have controls to move process to big or little.
I would ask a company which has an expertise on that topic and has different products to compare. This is something that usually nobody of us has here .. different systems and the time to test properly.

Congrats :-)

...and they will make everything worse...just wait and see...not holding my breath!