Sonar X1 with amazing PC, yet still horrible lag, help! stumped!

Hey guys, I recently purchased a Roland Octa-Capture 10x10 and it came with Sonar X1.
I have an electric drum kit plugged into channel 1 and USB out to the PC. I have buffer to 60mms and still get occasional lag, and even the metronome has slowed down at the end of a song during recording, wtf!?
I have task manager performance tab up to see if the CPU or anything else is being maxed and it doesn't appear as so, not even close, I don't think anything went beyond 5-10% usage.  
Since the interface is connected via USB, I do not have a sound card, just the one with the mobo. All research I do recommends ASIO drivers but those only appear to be for sound cards, but I don't think I'd need one since I have USB connectivity.
I looked at the input and playback which is at 44100 with 24 sampling, and made sure that matched the program. I basically can't record anything and feel comfortable unless the buffer is at 60 or 70, which is way too high to accurately record another track over the drums without excessive splicing.
Another issue is during playback, some parts will sound distorted, yet when I play the same track back a second time, that same part of the track isn't any longer distorted.
I'm completely at a loss, does anyone have any recommendations?  
 
Thanks!!!
-Ivan

Install the Octa-Capture's most recent ASIO drivers and use those.

Sonar need to run with ASIO drivers or you'll have all sorts of issues. 
Your problem sounds like you didn'tfollow the instructions to install the drivers correctly. 
Make sure to follow what it say's. Sometimes it's a simple matter of not plugging in the device until told to do so. 
 
But still you are always best to install the most up to date ASIO drivers for your audio interface. 
You don't need your on board sound chip for Sonar. Some like me even disable it. 
I use my audio interface and ASIO drivers for all things audio with my DAW computer. 
What's happening to you is your timing master is POS re- MME,, , this will go away once you set your Octa capture up properly. 
 
Not sure which drums you have but my Yamaha's needed the supplied USB drivers to work correctly with Sonar. 
I record to midi via USB and use Session drummer for playback, If you have X1 LE it won't have very good drum sounds. Use your copy to upgrade to Artist, Professioal or Platinum. That's what I did. 

And before anyone asks, the sound card is the onboard Realtek sound card, do I need to have an independent sound card?

Actually, lots of people run two sound cards with no problems, although disabling the onboard audio can avoid potential conflicts. Personally, I've always had the onboard audio disabled and use my external (Firewire-connected) interface for all sound. Like KR says, there is really no need to have the RealTek in the picture at all. It can be disabled via Device Manager.
 
There is no functional difference between an integrated audio interface such as the RealTek, a plug-in card like a SoundBlaster, and your Octa-Capture. They all do the same thing, and they all will run better on ASIO than MME, which has internal overhead that makes it unsuitable for real-time monitoring.
 
With your machine specs, you should have no problem getting 5.8ms or better. If you can't, it's because something is hogging resources. Topping the list of suspects would be your network adapter, especially if it's wi-fi. Get a copy of LatencyMon. Instructions for using it can be found here. This will measure DPC (interrupt-handler) overhead, which is not detectable via the Windows CPU monitor.
 
The intermittent distortion could be an indication of occasional high DPC latency caused by a hardware driver. If that's the case, LatencyMon will show you how bad it is, and help you identify which process is causing the most problems.