HELP! computer issues

Hello
I am really perplexed at what is going on with my computer and X3. I'm running a 32 track project and it stops sputters echoes all kinds of things. Addictive drums will not run unless I freeze the track.  What I noticed is the performance module is only showing two CPUs running when it is a quad core. I have multi-processor check but only seem to be running two. When I bring up Task Manager all four are running. I'm not sure what to do other get a new computer altogether. Here is my system, any ideas?

Thank you, Will 


Operating System System Model
Windows 7 Ultimate (x64) Service Pack 1 (build 7601)
Install Language: English (United States)
Enclosure Type: Desktop
Processor a Main Circuit Board b
2.60 gigahertz AMD Athlon II X4 620
512 kilobyte primary memory cache
2048 kilobyte secondary memory cache
64-bit ready
Multi-core (4 total)
Bus Clock: 200 megahertz
Drives Memory Modules c,d
2000.41 Gigabytes Usable Hard Drive Capacity
620.26 Gigabytes Hard Drive Free Space
_NEC DVD_RW ND-2500A ATA Device [CD-ROM drive]
PIONEER BD-RW BDR-208D ATA Device [CD-ROM drive]
3.5" format removable media [Floppy drive]
ST1000DM003-1CH162 [Hard drive] (1000.20 GB) -- drive 1, s/n W1D20T1G, rev CC47, SMART Status: Healthy
WDC WD10EARS-00MVWB0 [Hard drive] (1000.20 GB) -- drive 0, s/n WD-WMAZA6736391, rev 51.0AB51, SMART Status: Healthy
 
20 gigs memory

Hi When you say Which sound drivers I'm using ASIO on a Tascam US 1641 and I'm not sure what you mean "configured your host drive cache settings?" Could you explain more. Thanks

OP Wibil..I think you should edit your details and remove certain things that are not necessary to put in a open forum...S/n? are they key codes?

When was your last windows update ?
And have you tried a reboot of both PC and Tascam ?
 
When something like this happens to me I typically start from the ground up.
I power off everything, devices, exc.. then I unplug/re-plug in all cables (USB ports, 1/4 jacks, exc).
This way I know my RAM has been cleared out and my insert points have been re-examined.
A windows update is sometimes critical for the way Sonar processes, but not always the root of the problem. 
 
I have had similar problems like this because of a bad USP cable / A bad USB port.
My devise would work but not to full potential.

Thank you all for your help, I will try checking out some of these suggestions.
Will 

frragnarsson
Have you ruled out heating issues and that the cpu is throttling? Old thermal paste?

Good theory, but im partial to believe it based on 2 cores are showing, while 2 cores are not showing (within sonar) I give you props though. good reply as ive had thermal paste dry up on me before and it was a horror show to track down as I tried everything under the sun before (the last thing I checked) I checked the contact.
You are also correct in theory of thermal paste drying out because of heating issues. that stuff is hard to fry but a hot CPU, bad cooling, poor circulation will do it.
 
He said his Task manager shows all 4 virtual cores running so im curious if the OP made any changes to AUD.Ini or any other sonar files. I would also check AMD website for a BIOS update or even another update possibly skimping on CPU in software applications.