I don’t think you’re right about that. If I can run Nuendo and produce commercial content on a Phenom 9950 (this was last year, so a 9 year old CPU or whatever it was, Windows 7 x64) then the CPU is of course not an issue. So I agree that it’d be worth looking at the interface at that point. Especially if as you say you have the same experience on other computers with the interface being the common denominator.
However, if the interface and/or the driver was that poor then a lot of people would have a lot more problems. The usage you suggest is very simple. Just playing back Spotify is ‘nothing’, so it implies that users doing more heavy work should see worse issues. And if they generally did the internet would be filled with criticism of this interface (or the drivers). In fact, I don’t even think it would sell at all.
So, I would suggest you look into your setups more in detail and try to troubleshoot it. This isn’t the thread for it, so start a new one. Include:
- Used software including version number
- OS version and build
- Computer hardware
- Interface model number
- interface firmware number (if applicable)
- Interface driver version
etc…