Do I lack stability if I will perform my gigs with a hp 4730s and windows 7? I just dont have the cash to buy me a mac :\

Yes, You will have stability, a I7 machine, Very Good

I just add a stick 4Gb RAM

My vaio is similar, and Works Great

DELETED

Apple's Snow Leopard arrived during the twilight zone between the completion of Microsoft's Windows 7 and its general release.
The Snow Leopard media was built in early August and shrink-wrapped and on sale late the same month. Windows 7 went gold in late July, but will not appear on the high street until October 22nd.
The reason for the three-month delay on Windows 7 is so Microsoft's partners can create their custom builds, complete with third-party utilities, trial subscriptions and OEM branding that can be detrimental to the user experience. The culture is different to Apple's carefully crafted marriage of hardware and software into one seductive package.


Regards,
Selva

Leopards have 4 legs so are inherently more stable than windows which have to be precariously balanced on a narrow edge.

if you want a rock solid windows,beside good and updated drivers and hardware,do not install anything illegal.