problem on OS windows 7

[solarmystic]

Number 1 culprit for this situation is usually the drivers.

Depending on the age and model of your graphics card, the OpenGL driver for XP could be superior as compared to the one provided by your vendor for Windows 7 and above. This is particularly the case if your system was built/produced prior to the release of Windows 7/Vista.

I think I've read somewhere that the overhead for OGL is higher in Vista/7/8 as compared to XP for the same graphics card, since it has to jump more hoops to do the same thing. Again, this is highly dependant on your graphics card and how old it is. E.g. If you're on a card like the Radeon X series (2004/2005), the XP drivers are definitely superior to ones that AMD/ATI provides for Vista/7/8.

Number 2 culprit would be the additional demands of Windows 7 as compared to Windows XP on your system. For example, Aero Glass actually saps GPU power away from the emulator, and if your card is weak enough, you will notice the difference.

In conclusion, if your system is particularly ancient, it's best to stick with XP for the emulator.