hmm yeah this pc looks a bit dated to be playing SR2 at all high settings. Thats a single core processor, yes?
try to drop the settings down a bit and see if it still speeds up like that.
Saints Row 2
Publisher: THQ
Developer: Volition Inc.
Minimum System Requirements
OS: Windows XP/Vista
Processor: Intel Core 2 Duo @ 2.0 GHz / AMD Athlon 64 X2 3800+
Memory: 1 Gb
Hard Drive: 15 Gb free
Video Memory: 128 Mb
Video Card: nVidia GeForce 7600 / ATI Radeon X1300
Sound Card: DirectX Compatible
DirectX: 9.0c
Keyboard
Mouse
DVD Rom Drive
Recommended System Requirements
OS: Windows XP/Vista
Processor: Intel Core 2 Duo @ 3.2 GHz / AMD Athlon 64 X2 6400+
Memory: 2 Gb
Hard Drive: 15 Gb free
Video Memory: 256 Mb
Video Card: nVidia GeForce 8800 / ATI Radeon HD 3850
Sound Card: DirectX Compatible
Network: Broadband Internet Connection for Online Multiplayer
DirectX: 9.0c or 10
Keyboard
Mouse
DVD Rom Drive