When I boot the game I'm currently trying to play (Shenmue 1 PAL) everything runs smoothly at almost full speed.
After a few minutes the framerate drops heavily indipendently from where I am in the game (obviously the more stuff there's on screen, the more it drops). The only solution I found to make it go back to full speed has been to change the resolution from the NullDC menu: changing to any resolution briefly solved the problem, then I had to do this again. Problem is that after doing it multiple times times the emulator crashes.
Windows 7 64bit SP1
Intel Core i7-2630QM CPU 2.00Ghz (up to 2,9), 4,0GB RAM
NVIDIA GeForce GT 540 M, up to 1760 MB RAM
NullDC 1.0.4 Settings (I left the default options where not specified)
Graphics, nullDC PowerVR -- Direct3D HAL
GDRom, Image Reader plugin by drk
Sound, nullDC AICA
Sound CPU, VBA ARM Sound Cpu Core
Input, PuruPuru (I'm playing with a PS3 controller tricking the computer into thinking it's a Xbox360 controller)
Saves, nullDC VMU
Ext Device, nullExtDev
Enable CP Pass
Cable, VGA (1) (I'm playing PAL)
System Region & Broadcast Format, default
Palette Textures, versioned
Modifier volume, off
Thank you in advance!