I have tried everything in Sonar Producer 8 Options/Audio and can not get the audio record to run smoothly.  It stops after about 8 seconds and sometime stops recording altogether or sometime goes on after hesitation for another 8 seconds and stops.  I have been able to go from 1 or 2 seconds to 8.  The Record I/O Buffer is what I have been able to make the most progress with, however it is at 2048 kb which is the max size it will go.
Using Windows XP SP3  Pentium 4 at 2.8 Gig with 2 Gig Ram.  USB Interface Tascam US600.  

I have defraged the hard drive.  I have monitored the processor during these drop-outs and it is running at only 65% or less. 

Midi seems to work OK.  I have used the Tascam drivers (have gone to web site for latest version which is same as on provided disc and also used AOIS4ALL v.2 both have the same results.  I have also used WDM/KS and MME (32Bit) With same results.  I have played with every setting and was able to achieve smooth play back of pre-recorded audio, but when I attempt to record audio it begins the stop and go.  Also it seems not to be consistent in "kicking into" record mode.  I can get it to record, (with the stop and go problem) but when I go into the Options/Audio to try another adjustment in Buffer size and go back to make another test, the red record buttons will light red, but I get no response from the audio meters, hense nothing records (but the movement is smooth).  I have tried shutting down and restarting, making changes and then at times for no apparent reason the audio meters will start showing action.  I have become very frustrated after spending much time with this problem and while I seem to never get it to work, I do make some progress.  I have gotten other software (PowerTracks Pro Audio 2013) to work with this set-up but really what to use Sonar as there are so many more adjustments and options I would like to use.


Any Suggestions??    Thank You.

Tascam XP drivers.. I will say no more. Upgrade to Windows 7 or buy another interface

While I don't like the answer, I do appreciated that information.  Guess for now i will just use the PowerTracks Pro which seems to work fine.
Thanks Cactus Music!

As you'll see in my signature I too own a Tascam interface. I fought with the drivers for a few years with XP/ The minute I switched to W7 -64 bit it has been rock solid now and I have had no issues. 

I have a xp 32 bit- P4 Laptop and I use it  for live audio recording with no problems with the Tascam. But I cannot use it beyond that. It will behave in all manners of frustration if I try and add any soft synths or even basic plug in efxs. 
 

Cactus Music, you were so right!  I loaded Sonar and moved Tascam us600 to my Windows 7 64bit computer and it worked fantastic.  I wanted to have a computer just dedicated to making music and that was my reason for buying the Sonar 8 and Tascam because all my reading stated that they would work on my existing Windows XP computer.  Well, I am resolving the problem by purchasing a refurbished Windows 7 64bit computer and will make that my music making computer.  Thanks for your help, wish I would have know all this several weeks ago.

While I don't use a tascam interface, (I use Motu) I did recently upgrade from Vista Ultimate 64 to win 7 pro, and am blown away by the stability that I'm having. I forgot how great life could be running glitch free.