GTA IV is slow as hell when i am in the main city, it's just slow idk why.
this is the benchmark result(also the default settings)
More 
Statistics
Average FPS: 21.84
Duration: 37.08 sec
CPU Usage: 97%
System memory usage: 89%
Video memory usage: 84%
Graphics Settings
Video Mode: 1024 x 768 (60 Hz)
Texture Quality: Medium
Render Quality: Medium
View Distance: 32
Detail Distance: 30
Hardware
Microsoft Windows Vista" Home Basic
Service Pack 2
Video Adapter: NVIDIA GeForce 9500 GT
Video Driver version: 196.21
Audio Adapter: Speakers (Realtek High Definition Audio)
Intel(R) Core(TM)2 Duo CPU E4600 @ 2.40GHz
in the graphics tab, there was 365MB out of 458MB used
so what is wrong?