100% CPU use in XP guest

[Wakou]

I run vbox to play poker. when I launch XP (a clean install) with only one poker client,and taskmanager open, the CPU usage in XP shoots up and fluctuates between 40% and 80%, sometimes maxing out at 100%.
If I run XP natively, even though my install is old and full of rubbish, cluttered registry, lots of unidentified processes running etc etc the CPU usage sits at < 10%.
This situation makes playing poker a frustrating and expensive experience, as I miss hands when changing windows etc. It also makes my host run slowly.
system specs in sig. Graphics are handled by an on-board nVidia gpu with 128Mb dedicated to it. I have allowed 870mb to the VBox/guest.
Why would the poker app (not hugely graphics intensive, nor number-crunching) take up so much resource under vBOX, but behave itself under windows native?

[vbox4me2]

With a clutered install impossible to say if anything is misbehaving, but add a second VM and let that run idle next to the main VM.

[Wakou]

With a clutered install impossible to say if anything is misbehaving,

Perhaps I was not too clear, the cluttered install is my native, boot to Windows XP, and is not an issue as I hardly use it. I only fired it up and mentioned it in the post to compare it with the performance of the same app in a VM

but add a second VM and let that run idle next to the main VM.

TY! Could you explain in a little more detail please? I have come across references to this kludge on google etc but did not fully understand, indeed I mentioned it on #vbox IRC channel and was dismissed as being unlikely.......
What do you mean by this?,
Does the second, dummy VM have to be Windows as well?
Or could I create a VM using say DOS or a very skinny Linux distro?
Does it actually have to be open and running?, or just installed/created?
Can it indeed be an "empty" VM?

TY agan for the help

[vbox4me2]

Start with an empty one, or a skinny linux.

[fr2000]

I am getting 100% CPU with SMP Guest with APIC-IO Active. For each core used in Windows Guest. Linux Guests don't race the CPU's to 100%...only windows guests...I am desperately trying to find out how to stop that problem. Making a striped Linux does not work next to a Windows Guest..for I tried 2 of them with my Windows guests...no dice.

Is there any solution to fix the Windows SMP Guests from racing each core of the CPU's of the Linux host?