ATTO's Disk Bench scores are very interesting to look at. The benchmark actually writes chunks of data to the harddisk(s) which vary in size from 0.5 KB to 1024 KB. What is interesting, though, is that the smaller data chunks are being transferred slower than bigger ones; the sweet spot for the 10K seems to be around 16 KB, whereas the 10K II's is around 64 KB, from then on the throughput basically levels out. This is consistent with what we'd expect, as it takes longer to locate and read/write a few small chunks than one bigger one. As for the difference between the two disks, the 10K II's bigger cache certainly comes into play here, too.
A good overall impression can be obtained by just adding all of the values for the different chunk sizes and then dividing by the number of chunks for both read and write operation. Start by individually adding the numbers for read and write and then add up the total for read and write and divide by two, divide this number by twelve, as we have twelve different chunk sizes, to get the overall throughput. If we then compare the two disks, we can see that the Atlas 10K II has a full 115% higher throughput.
Average Overall Throughput Atlas 10K: 20519 KB/s
Average Overall Throughput Atlas 10K II: 44096 KB/s
Average Performance Increase: (44096/20519) x 100% = 115%
TCD Labs' HDtach shows a somewhat similar picture; notice the burst transfer rates, which is actually data being read from the harddisk's buffer, and are close to 80 MB/s. A non-Ultra160 controller might be running into trouble here. If we again compare the two disks we can see that the Atlas 10K II has a more than 50% higher throughput overall than the Atlas 10K.
Average Overall Throughput Atlas 10K: 21961.9 KB/s
Average Overall Throughput Atlas 10K II: 33331.1 KB/s
Average Performance Increase: (33331.1/21961.9) x 100% = 52%
The SiSoft Sandra 2000 scores are equally conclusive: the Atlas 10K II beats the Atlas 10K by 54%. Take notice, however, that the Sandra 2000 scores are a performance index, and don't show actual drive throughput.
Drive Index Atlas 10K: 18208
Drive Index Atlas 10K II: 27970
Average Performance Increase: (27970/18208) x 100% = 54%
Overall the Atlas 10K II proved to be a good bit faster than the 10K II, the combination of 10.000 RPM spindle speed and a 8 MB data buffer allowed for some impressive disk throughput scores.