Hi!
I have Dell Optiplex 755 machine with core 2 duo 3 ghz (6Mb Cache) processor, 8 Gb 800mhz of Ram n WD SATA 2 Tb (64Mb Cache) Hard Drive and M-Audio Fast Track Ultra audio interface.
I installed the clean fresh Win 7 Pro 64bit then installed Sonar X1 PE then i installed Pro Tools 10 HD. When i set my Sample rates to 24bit/96khz and 64 bit double precision engin ON in SONAR, it plays glitches and pops, but works good with 16bit/48khz and 64bit Double precision engin ON. But pro tools works good with 24bit/96. I also have SONAR 7 PE installed on my machine, it does the same even CPU usage n Disk usage meter shows a very little amount just less then 3 or 4 %.
Even having another trouble that my SONAR doesn't export an audio, even on 16bit/48khz rates, i tried to clear the tick from 64 bit double prec: engin from export audio options but it didn't work, Sonar just says "an error accrued exporting audio". But the "bounce to Track" option works perfectly.
Kindly help.

Just to be sure: You did install the 64 bit version of SONAR?
Did you have PT running simultaneously? In that case have "Share drivers with other programs" checked.
Did you try with different buffer sizes? And only M-Audio selected in I/O drivers and record/playback timing master?
You are aware of that only 16 bit/44,1 kHz can be used for CDs, aren't you? 48 kHz is for DVDs, though.
How are you routing your audio? Everything through Master Bus is the recommended way. Then use Master Bus as the export source.

Best to set it at 44100 x 24 or 32 bit. You can render at 32 or 64 if you prefer.
I get the best results just going at 44100 x 24 bit. I bounce and render at 24 bit.
 
There are many plug ins that are not supported at 64 bit and that could be an issue.
 
Store bought CD's are 16 bit. They made that choice because the human ear can only hear so much. You probably can not tell the difference in a 24 or 32 bit recording, but you can tell the difference in a 16 bit data file compared to an audio CD or a 24 bit recording.