An SSD made my Late 2008 MBP very quick. As you can see, the 4k read/writes of the SSD kick the heck out of the HDD.
7200 rpm HDD
Results 144.53
System Info
Xbench Version 1.3
System Version 10.5.7 (9J61)
Physical RAM 4096 MB
Model MacBookPro5,1
Drive Type ST9320421AS
CPU Test 168.87
GCD Loop 288.49 15.21 Mops/sec
Floating Point Basic 143.04 3.40 Gflop/sec
vecLib FFT 117.66 3.88 Gflop/sec
Floating Point Library 211.40 36.81 Mops/sec
Thread Test 316.92
Computation 466.74 9.46 Mops/sec, 4 threads
Lock Contention 239.91 10.32 Mlocks/sec, 4 threads
Memory Test 186.83
System 220.06
Allocate 281.26 1.03 Malloc/sec
Fill 183.22 8908.51 MB/sec
Copy 216.49 4471.52 MB/sec
Stream 162.31
Copy 152.91 3158.36 MB/sec
Scale 158.10 3266.27 MB/sec
Add 169.75 3616.10 MB/sec
Triad 169.84 3633.33 MB/sec
Quartz Graphics Test 207.66
Line 191.95 12.78 Klines/sec [50% alpha]
Rectangle 252.21 75.30 Krects/sec [50% alpha]
Circle 205.62 16.76 Kcircles/sec [50% alpha]
Bezier 200.78 5.06 Kbeziers/sec [50% alpha]
Text 197.64 12.36 Kchars/sec
OpenGL Graphics Test 149.25
Spinning Squares 149.25 189.34 frames/sec
User Interface Test 333.48
Elements 333.48 1.53 Krefresh/sec
Disk Test 51.31
Sequential 102.23
Uncached Write 97.94 60.14 MB/sec [4K blocks]
Uncached Write 120.83 68.36 MB/sec [256K blocks]
Uncached Read 73.84 21.61 MB/sec [4K blocks]
Uncached Read 140.85 70.79 MB/sec [256K blocks]
Random 34.25
Uncached Write 10.95 1.16 MB/sec [4K blocks]
Uncached Write 149.64 47.91 MB/sec [256K blocks]
Uncached Read 84.57 0.60 MB/sec [4K blocks]
Uncached Read 143.17 26.57 MB/sec [256K blocks]
128GB SSD
Results 201.60
System Info
Xbench Version 1.3
System Version 10.5.7 (9J61)
Physical RAM 4096 MB
Model MacBookPro5,1
Drive Type SAMSUNG MMCRE28G5MXP-MVB
CPU Test 170.44
GCD Loop 295.02 15.55 Mops/sec
Floating Point Basic 143.36 3.41 Gflop/sec
vecLib FFT 119.33 3.94 Gflop/sec
Floating Point Library 211.75 36.87 Mops/sec
Thread Test 318.00
Computation 380.01 7.70 Mops/sec, 4 threads
Lock Contention 273.39 11.76 Mlocks/sec, 4 threads
Memory Test 188.24
System 222.80
Allocate 291.29 1.07 Malloc/sec
Fill 184.51 8971.17 MB/sec
Copy 216.81 4478.17 MB/sec
Stream 162.97
Copy 153.47 3169.85 MB/sec
Scale 153.92 3179.91 MB/sec
Add 175.19 3731.93 MB/sec
Triad 171.70 3673.11 MB/sec
Quartz Graphics Test 210.09
Line 195.21 13.00 Klines/sec [50% alpha]
Rectangle 253.63 75.72 Krects/sec [50% alpha]
Circle 207.41 16.91 Kcircles/sec [50% alpha]
Bezier 202.20 5.10 Kbeziers/sec [50% alpha]
Text 201.33 12.59 Kchars/sec
OpenGL Graphics Test 154.03
Spinning Squares 154.03 195.39 frames/sec
User Interface Test 312.93
Elements 312.93 1.44 Krefresh/sec
Disk Test 168.07
Sequential 134.50
Uncached Write 106.10 65.14 MB/sec [4K blocks]
Uncached Write 139.42 78.88 MB/sec [256K blocks]
Uncached Read 96.44 28.22 MB/sec [4K blocks]
Uncached Read 360.57 181.22 MB/sec [256K blocks]
Random 223.99
Uncached Write 122.76 13.00 MB/sec [4K blocks]
Uncached Write 136.48 43.69 MB/sec [256K blocks]
Uncached Read 1657.11 11.74 MB/sec [4K blocks]
Uncached Read 561.42 104.18 MB/sec [256K blocks]