Okay, this one was just for laughs:
LaunchGTAIV.exe -benchmark -renderquality 4 -shadowdensity 16 -texturequality 2 -viewdistance 99 -detailquality 99 -novblank -norestrictions -width 1920 -height 1200 -refreshrate 60 -fullscreen -fullspecaudio
16 FPS with the very highest settings vs. 24 FPS with the very lowest settings.
LaunchGTAIV.exe -benchmark -renderquality 4 -shadowdensity 16 -texturequality 2 -viewdistance 99 -detailquality 99 -novblank -norestrictions -width 1920 -height 1200 -refreshrate 60 -fullscreen -fullspecaudio
Statistics
Average FPS: 16.27
Duration: 37.49 sec
CPU Usage: 81%
System memory usage: 81%
Video memory usage: 98%
Graphics Settings
Video Mode: 1920 x 1200 (60 Hz)
Texture Quality: High
Render Quality: Highest
View Distance: 100
Detail Distance: 100
Hardware
Microsoft Windows XP Professional
Service Pack 3
Video Adapter: NVIDIA GeForce 8800 GTX
Video Driver version: 180.84
Audio Adapter: SB X-Fi Audio [CC00]
Intel(R) Core(TM)2 CPU 6300 @ 1.86GHz
File ID: Benchmark.cli
16 FPS with the very highest settings vs. 24 FPS with the very lowest settings.