I can't help you much, just would like to say that in my experience the quality of the soundcard driver and how it matches with your OS is the most critical component of any audio PC. In the past I've also experienced problems with the wireless connection of the computer causes glitches in playback and recording, and only way to get around it was to physically disable the hardware. 
Just to mention, I have several audio PC's ... the one I'm using at the moment is a win7x64 lenovo X201 laptop with i5 processor, 8 GB, 250 GB SSD, and a "not recommendable" Akai EIE Pro interface. Using ASIO drivers of course. I have 25 ms round trip latency.
... <Break> ... 
For some strange reason as I was gonna test it ... it became all glitchy as well ... will get back on this :) 
Used to work all fine. 
[Edit] Turning off the wifi removed my problem. I'm usually, except now able to have it on without problem.
I guess also anti virus and network operations in general can cause problem for real time audio ... it's seems 
a little bit random ... as know I'm able to have the wifi on as I'm writing this ... and previous problems seems 
to have gone away. So it's hard to say that it was actually that which was the problem.
 

mattburnside
So I replaced the Toneport UX2 and things went from bad to worse.
 
Got a brand new Focusrite Scarlett 2i2 and the round trip time is up, crackles are increased and processor useage display in Sonar seems to be sky high all the time.
 
Drivers up to date and everything I'm not using has been disabled, anyone experience with the 2i2 and any quirks with Sonar I could be missing?
 
Thanks

Focusrite advice is to plug the interface in a USB2.0 port; maybe yours is connected in a USB3.0.

I missed this post on its first run, but your post #23 with the LatencyMon sticks out like a sore thumb just because of the number of svchost.exe entries shown. Gut feel is that you have a lot of programs loading when you start Windows, so I would focus on that one first. I do not have time to type detail at the moment, but another comment with that LatencyMon post:
 
Could you run that again and post the "Process" tab, but click on the "Hard Pagefault" column to get the highest number at the top? (I think you have to click the column header twice to get from high to low). The first tab is showing processes, and I am curious as to what they are.
 
At a very high level, there are a lot of items that are not optimized for Windows itself, and one of the easiest ways to get these is with the free version of iObit's Advanced System Care (can run that, scan/fix everything (and even uninstall afterwards if desired)).
 
I will need to revisit this thread later, but if you are familiar with looking at processes running on your machine (Task Manager when you hit ctrl-alt-delete), you can start to look at what things are running in the background and chewing up your resources. That LatencyMon post leads me to think you are not suffering a driver issue, but a system configuration issue.

Bottomline is if you are going to run your daw, give you computer a chance to focus on just that.  Disable any programs running at bootup (that is except your soundcard).  If you have to, create a separate boot-up configuration for using your daw.

If you were looking for better performance a 2i2 is a very low end interface. It is similar to my 6i6. 
But I agree with mettalus. You need to optimize your PC first. 
And you cannot expect to run a low buffer settings with the way things are. 
I run mine at 256 and it is rock solid. But I don't care about RTL because I use direct monitoring only.