Old dusty pc runs this game better than my new one

[BDK]

Hi all, I have a question that has been baffling me for years ..

My old PC ran this game super smooth in 1080p. Specs:
- AMD64 3200+ (2ghz)
- 2GB DDR RAM
- Geforce 8800GTS (320MB)
- Windows XP

While my new PC (built a year ago) drops below 15fps at the starting area where you see the 3 gates (the very beginning of the game). Specs:
- AMD Athlon II X4 640 (3ghz, quad)
- 4GB DDR3-1333mhz RAM
- Radeon 5770 1GB
- Windows 7

In all other games my new PC performs excellent, like night & day compared to my old PC. However in Kings Bounty it seems to be reversed for some reason and it's the very reason I have not purchased Armored Princess and Crossworlds.


Any ideas? Drivers / bios etc. are up-to-date.