Desperately Need Help With Latency Issue

I had older hardware and software before and did not have latency issues. My current setup has been investigated by me and a DAW professional, changing every setting imaginable, plus I’ve written others and I cannot find a cause for my problem. The latency test is simply recording a metronome and then recording clapping to that, i.e. 2 tiny audio files, no softsynths, etc.
 
My setup is:
 
Rain laptop with 2.3GHz Intel "Ivy Bridge" Core i7 Quad-Core Processor, 8gb RAM, 500gb hard drive running Windows 8 64-bit.  (I had an old Rain computer that worked well, but couldn’t support new software.)
 
Tascam US-366 (I had an older Tascam unit that worked great but doesn’t have drivers for my current setup). Unit connects to laptop via USB 2.0 with a 2.0 cable. Latest driver installed.
 
Sonar X2 Producer
 
When I set the settings very low, I never get any popping, but there's always noticeable delay.
 
I have tried installing Sonar on computer running Windows 7 32-bit, and had the exact same issue. I have yet to hear back from Tascam.
 
ANY HELP IS APPRECIATED.  Is it possible my hardware will simply not work together? Is the audio interface the most likely culprit?
 
Many thanks, John

I was recently made aware that running a USB 2.0 audio interface on a USB 3 port can cause problems like this. Does your laptop offer USB 2.0-only ports? Try connecting to a different port in any case.