Benchmark Results: I/O Performance And Access Time
All I/O performance tests reveal that the 640GB two-platter drive is faster. Since the difference is pretty large, it's obvious that high I/O performance wasn’t part of the 1TB model's performance requirements.
Access time is longer on the three-platter drive, which corresponds to what we’ve seen in I/O testing.
At this point, we have to assume that the high-capacity drive was optimized for throughput, while the 640GB model received firmware more suitable for I/O intensive workloads.