six.four is right on the money. PATA is not the limiting factor in the SSD performance of the 1.8/64GB.
It looks like I am going to add to my Xbench numbers, but it does make for an interesting comparison:
Mac Mini (80GB 5400rpm):
Sequential 67.22
Uncached Write 69.74 42.82 MB/sec [4K blocks]
Uncached Write 68.11 38.54 MB/sec [256K blocks]
Uncached Read 55.76 16.32 MB/sec [4K blocks]
Uncached Read 79.68 40.04 MB/sec [256K blocks]
Random 27.02
Uncached Write 9.39 0.99 MB/sec [4K blocks]
Uncached Write 65.57 20.99 MB/sec [256K blocks]
Uncached Read 63.56 0.45 MB/sec [4K blocks]
Uncached Read 94.63 17.56 MB/sec [256K blocks]
Macbook Pro (200GB 7200rpm):
Sequential 80.05
Uncached Write 82.40 50.59 MB/sec [4K blocks]
Uncached Write 96.00 54.32 MB/sec [256K blocks]
Uncached Read 56.37 16.50 MB/sec [4K blocks]
Uncached Read 103.38 51.96 MB/sec [256K blocks]
Random 26.24
Uncached Write 8.10 0.86 MB/sec [4K blocks]
Uncached Write 100.76 32.26 MB/sec [256K blocks]
Uncached Read 88.54 0.63 MB/sec [4K blocks]
Uncached Read 127.53 23.66 MB/sec [256K blocks]
Macbook Pro (128GB SSD):
Sequential 71.28
Uncached Write 107.34 65.91 MB/sec [4K blocks]
Uncached Write 69.55 39.35 MB/sec [256K blocks]
Uncached Read 36.98 10.82 MB/sec [4K blocks]
Uncached Read 185.97 93.47 MB/sec [256K blocks]
Random 115.88
Uncached Write 45.71 4.84 MB/sec [4K blocks]
Uncached Write 102.46 32.80 MB/sec [256K blocks]
Uncached Read 1187.04 8.41 MB/sec [4K blocks]
Uncached Read 490.77 91.07 MB/sec [256K blocks]
Macbook Air 1.0 (1.8GHz/64GB SSD)
Sequential 40.82
Uncached Write 33.92 20.83 MB/sec [4K blocks]
Uncached Write 46.51 26.32 MB/sec [256K blocks]
Uncached Read 27.24 7.97 MB/sec [4K blocks]
Uncached Read 97.00 48.75 MB/sec [256K blocks]
Random 56.13
Uncached Write 21.06 2.23 MB/sec [4K blocks]
Uncached Write 52.85 16.92 MB/sec [256K blocks]
Uncached Read 990.68 7.02 MB/sec [4K blocks]
Uncached Read 259.96 48.24 MB/sec [256K blocks]
The interface does have a slight effect on it, but the gap is not as wide as I originally anticipated it would be.