Here's my setup at the time of testing:
Power Tower Pro
Mac OS X 10.3.9
CPU: 750GX on XLR8 CarrierZIF
Bus/CPU clock: 57MHz/1026MHz
RAM: 1GB
Drives: Seagate 15k.3 36GB; Seagate 7200.7 200GB and 7200.8 300GB with Acard IDE-SCSI adapters
PCI slots:
A1: Adaptec 39160
D2: Radeon 9200 PCI

Resolution: 1024x768 @114Hz
PCI Extreme is on.
Radeon PCI High Performance setting is on.

I did tests at 33MHz PCI and 66MHz PCI with QuickBench on the 15k.3, Let1kWindowsBloom, Unreal Tournament 2004 and with the XBench graphics benchmark.

For the QuickBench tests I just did the larger extended tests since measuring highest sustained throughput was the main goal. I may add the other benchmarks later.

Test Size 33MHz Read 66MHz Read 33MHz Write 66MHz Write
20 MB
30 MB
40 MB
50 MB
60 MB
70 MB
80 MB
90 MB
100 MB
 50.127
51.061
51.013
49.609
51.256
51.048
51.280
51.263
51.294
 70.082
72.045
71.968
72.340
72.137
72.319
72.414
72.401
72.421
 39.921
39.892
40.054
40.102
40.091
40.081
40.103
40.188
40.161
 60.934
61.093
61.214
61.238
61.260
60.935
52.756
61.059
60.890

XBench Quartz Graphics Test
Test 33MHz 66MHz
Overall
Line
Rectangle
Circle
Bezier
Text
 14.81
14.97
7.78
11.39
38.05
35.32
 19.37
18.85
10.61
15.01
45.26
45.11

XBench OpenGL Graphics Test
Test 33MHz 66MHz
Spinning Squares
 14.85 19.59

XBench User Interface Test
Test 33MHz 66MHz
Elements
 4.69 5.90

Let1kWindowsBloom (33MHz): 44 sec
Let1kWindowsBloom (66MHz): 38 sec

For the Unreal Tournament 2004 benchmarks I used the Asbestos flyby with graphics on. Botmatch was also asbestos, graphics on, sound off. Both were done for minimum and maximum detail settings.

Benchmark 640x480 800x600 1024x768 1280x1024 1600x1200
Flyby 33MHz (Min)
Flyby 66MHz (Min)
Flyby 33MHz (Max)
Flyby 66MHz (Max)
 29.52
38.94
23.85
31.19
 30.14
38.02
29.21
23.14
 28.30
37.36
21.96
28.61
 27.02
34.97
19.88
25.11
 22.34
33.45
18.16
26.07
Botmatch 33MHz (Min)
Botmatch 66MHz (Min)
Botmatch 33MHz (Max)
Botmatch 66MHz (Max)
 14.51
17.01
8.63
10.50
 14.48
16.92
8.63
10.44
 14.05
16.50
8.25
10.16
 14.24
17.23
7.51
9.17
 12.57
15.18
7.51
9.28