Just throwing this out there to see if anyone has had a similar problem:   I’m a low end user who, for several years used a Tascam US2000 into Sonar platinum pro.    I am using a quad core AMD machine running windows 10
 
The interface was quite adequate when mixing, but would start to break up a little on songs  with more than 16 tracks, or with  a lot of effects, even though CPU, disk and memory usage were all below 50%.  That wasn’t too much of a problem, as it could be solved simply by increasing the buffer size on the Tascam.  However,  I didn’t like the mic preamps much( noisy) and eventually relegated the US 2000 to a friend’s studio.
 
I was thinking of purchasing a larger Focusrite, but bought a 2i2 as an initial test.  The mic pre-amps sound much better and it works great with single vst instruents and a small number of tracks   However the 2i2 breaks up with some very obnoxious clicking whenever I approach 14- 16 tracks, and  this cannot be prevented by increasing the buffer size.   In case the machine was inadequate, I traded it on a 3^rd gen i7 machine,  running Sonar platinum.  The problem was every bit as bad. It is essentially useless at the moment
 
 I am in contact with Focusrite, but the response hasn’t been encouraging so far  “try our latest drivers….that didn’t fix it?  Well … Windows is not very good at handling audio…..   try this long list of things that involve completely removing all other functionality from the machine.”
 
I’m not against the idea that a music computed shouldn’t  be doing other things, but I am annoyed that the Tascam, and EVEN A BEHRINGER UCA222 will work under circumstances where  the Focusrite won’t.
Anyone had any experiences with this?   Were Focusrite able to pinpoint the problem, or am I in for a month of  wasted effort changing system parameters? 

I run Focusrite Solo on Win10 on high spec PC i7 with 16Gb RAM.
I'm only running X3, but I do get some clicks when running larger projects (i.e. 16+ vst and/or audio tracks)
I normally resolve this by increasing latency on playback (normally up to 256 or maybe 512), but have to reduce it back down to record audio. 
I've found it better on the previous driver version (not the latest)
 
Sorry, probably not what you want to hear......
 
Also, I use my music pc for other uses as well. Try setting up a separate 'user' for music work, and make sure that user doesn't have OneDrive or any other network sync type tools running. Also disable antivirus if you us it. Make sure your normal user is logged off before recording, I tend to reboot the pc and log in as 'sonar' at the start of each session.
 
Hope this is helpful.... 

I use a first generation 2i4 running the latest drivers and don't have the problems you're describing

18i20 1st generation here with no issues. Win 10, i5 , 8 gb ram, off the shelf Dell running SPLAT.  Sorry no help, but wanted you to know it CAN work, and does for many people. good luck getting it sorted out. As you have already replaced the machine, I would start looking at things like 3rd party plug-ins, usb cables, try a different usb port, etc.

Using a Pro 40 here! I've mostly always used Focusrite audio interfaces and found them to be many times better than most others. I do always manage my projects efficiently though, by freezing tracks and doing all the recorded stuff first before ramping up the buffer for mixing. Many of my projects have 24 or more tracks including vst instruments such as Reaktor, Kontact loaded, Play loaded etc. and this is an AMD powered machine.

I can't help much.  I have 18i20 2nd generation on Win10.  I have been using it about a month and it has been fairly stable.  I have had a number of cases where I have to reboot or go in and reset Sound stetting on Windows (because Media Player or the web browser stopped sounding.  Under SONAR I have not had dropouts or clicks, but I haven't done really large projects in the last month.
 
Overall I would say the product hardware is great, but the software is not as stable as the Presonus I replaced.  OTOH, I replaced it because Presonus was deprecating software and firmware levels even though my Presonus i/f was still in current production.
 
So I don't know.  Is there anybody who makes an audio i/f that has really good preamps at an affordable price, together with good, stable software?

cparmerlee
 
So I don't know.  Is there anybody who makes an audio i/f that has really good preamps at an affordable price, together with good, stable software?

MOTU

Running an older Focusrite 8i6 - Win 10 on new computer (i7, 32GB RAM), SPLAT - no problems so far (computer is only a couple months old).  I know this doesn't really help you, other than to document that not everyone running a Focusrite USB interface on Win 10 with the latest drivers (and latest version of the mixer software) is having the same problem you are.  I'm not smart enough to know exactly what part of the system gets taxed the most with increasing track number and more effects, but still think it's possible that the problem may be with your setup and not with Focusrite per se.  (And, IMO the comment that 'Windows is not very good at handling audio' is false, at least at the level of the average home studio user). 

I had similar problems then, after reading some advice online, asked Focusrite for their latest beta driver. That has fixed my issues. May be worth asking!  

gustabo

cparmerlee
 
So I don't know.  Is there anybody who makes an audio i/f that has really good preamps at an affordable price, together with good, stable software?

MOTU

"an affordable price"