Okay, I performed some more benchmarks. I also added more RAM as someone suggested and took note to see how that impacted performance. Not the most comprehensive benchmarking but hopefully gives an idea:
FX5500, 128MB RAM, 61.76:
3DBench 1.0c - 306.1
Chris' 3D Bench (640x480) - 138.9
PC Player (640x480) - 31.1
Doom - 111.97
Quake (360x480) - 58.7
Quake (640x480) - 51.1
Quake III Timedemo - 95.1
3DMark99 - 4790
3DMark01 - 4326
FX5500 as 5200, 128MB RAM, 45.23:
3DBench 1.0c - 297.9
Chris' 3D Bench (640x480) - Failed
PC Player (640x480) - 30.4
Doom - 110.47
Quake (360x480) - 57.6
Quake (640x480) - 21.2
Quake III Timedemo - 94.8
3DMark99 - 5462
3DMark01 - 4347
FX5500 as 5200, 640MB RAM, 45.23:
3DBench 1.0c - 297.9
Chris' 3D Bench (640x480) - Failed
PC Player (640x480) - 30.4
Doom - 108.08
Quake (360x480) - 57.3
Quake (640x480) - 20
Quake III Timedemo - 97.6
3DMark99 - 5956
3DMark01 - 4419
MX440, 128MB RAM, 45.23:
3DBench 1.0c - 190.3
Chris' 3D Bench (640x480) - Failed
PC Player (640x480) - 30.3
Doom - 70.5
Quake (360x480) - 47.4
Quake (640x480) - 30
Quake III Timedemo - 98.8
3DMark99 - 5183
3DMark01 - 2416
MX440, 640MB RAM, 45.23:
3DBench 1.0c - 415.9
Chris' 3D Bench (640x480) - Failed
PC Player (640x480) - 30.3
Doom - 70.6
Quake (360x480) - 47.5
Quake (640x480) - 20
Quake III Timedemo - 101.8
3DMark99 - 6208
3DMark01 - 3051
MX460, 128MB RAM, 45.23:
3DBench 1.0c - 297.9
Chris' 3D Bench (640x480) - Failed
PC Player (640x480) - 30.5
Doom - 108.08
Quake (360x480) - 57.2
Quake (640x480) - 20.1
Quake III Timedemo - 99.3
3DMark99 - 6540
3DMark01 - 3655
(Just to clarify, other than Quake III and 3DMark, the above was all done in a DOS boot not from command line/prompt in Windows)