my laptop is an MSI S270. It is 4years old aprox. the proc is,I think, athlon MT37 (XP3000+).
The problem is not only with hypersonic2 but with all VSTi (hypercanvas, sampletank, sfz ...).
My soundcard is the fabulous Echo INDIGO PCMCIA. I say fabulous because it is a wondefull affordable card. very low latency and fantastic dynamic sound. if you have the occasion try it.

I will try with my other card, to check if the problem is from the echo.
other card is : line6 toneport ux1. good for guitar and mic input but not as good as the indigo for project monitoring.

thanx for the support