I've just finished upgrading my iMac 2.0GHz Core Duo to a 2.33GHz Core 2 Duo. Here are the results after the upgrade. I don't have any original results before the upgrade because honestly I didn't know if I was going to be able to do it. I wouldn't recomend the upgrade unless your machine is out of warrantee and you deal with circuit boards on a regular basis. I used John's directions on replacing the HD as a start (http://home.comcast.net/~woojo/) and additional pictures at http://www.kodawarisan.com/imac_intel/imac_intel001.html for additional info. From the HD replacement instructions the speakers, main circuit board needs and then heatsink need to be removed to get at the CPU. I wish I had pictures of this part, but I was more concern about getting something working once reassembled, sorry. I'd have to take the thing apart again and I'd say that is pressing my luck.
So far I haven't noticed any additional fan noise that would be expected with increased amount of heat from the Core 2 Duo if there is any over the Core Duo.
Results 175.95
System Info
Xbench Version 1.3
System Version 10.4.8 (8L2127)
Physical RAM 2048 MB
Model iMac4,1
Drive Type WDC WD2500JS-40NGB2
CPU Test 123.10
GCD Loop 276.41 14.57 Mops/sec
Floating Point Basic 139.11 3.31 Gflop/sec
vecLib FFT 98.43 3.25 Gflop/sec
Floating Point Library 86.75 15.11 Mops/sec
Thread Test 234.02
Computation 214.11 4.34 Mops/sec, 4 threads
Lock Contention 258.01 11.10 Mlocks/sec, 4 threads
Memory Test 129.71
System 131.76
Allocate 119.04 437.15 Kalloc/sec
Fill 134.53 6541.12 MB/sec
Copy 144.21 2978.60 MB/sec
Stream 127.72
Copy 117.49 2426.64 MB/sec
Scale 120.99 2499.59 MB/sec
Add 137.20 2922.73 MB/sec
Triad 137.89 2949.84 MB/sec
Quartz Graphics Test 152.40
Line 139.78 9.31 Klines/sec [50% alpha]
Rectangle 174.12 51.98 Krects/sec [50% alpha]
Circle 166.56 13.58 Kcircles/sec [50% alpha]
Bezier 151.76 3.83 Kbeziers/sec [50% alpha]
Text 136.64 8.55 Kchars/sec
OpenGL Graphics Test 189.37
Spinning Squares 189.37 240.23 frames/sec
User Interface Test 464.56
Elements 464.56 2.13 Krefresh/sec
So far I haven't noticed any additional fan noise that would be expected with increased amount of heat from the Core 2 Duo if there is any over the Core Duo.
Results 175.95
System Info
Xbench Version 1.3
System Version 10.4.8 (8L2127)
Physical RAM 2048 MB
Model iMac4,1
Drive Type WDC WD2500JS-40NGB2
CPU Test 123.10
GCD Loop 276.41 14.57 Mops/sec
Floating Point Basic 139.11 3.31 Gflop/sec
vecLib FFT 98.43 3.25 Gflop/sec
Floating Point Library 86.75 15.11 Mops/sec
Thread Test 234.02
Computation 214.11 4.34 Mops/sec, 4 threads
Lock Contention 258.01 11.10 Mlocks/sec, 4 threads
Memory Test 129.71
System 131.76
Allocate 119.04 437.15 Kalloc/sec
Fill 134.53 6541.12 MB/sec
Copy 144.21 2978.60 MB/sec
Stream 127.72
Copy 117.49 2426.64 MB/sec
Scale 120.99 2499.59 MB/sec
Add 137.20 2922.73 MB/sec
Triad 137.89 2949.84 MB/sec
Quartz Graphics Test 152.40
Line 139.78 9.31 Klines/sec [50% alpha]
Rectangle 174.12 51.98 Krects/sec [50% alpha]
Circle 166.56 13.58 Kcircles/sec [50% alpha]
Bezier 151.76 3.83 Kbeziers/sec [50% alpha]
Text 136.64 8.55 Kchars/sec
OpenGL Graphics Test 189.37
Spinning Squares 189.37 240.23 frames/sec
User Interface Test 464.56
Elements 464.56 2.13 Krefresh/sec