Here it is, Seagate's newest 3.5" enterprise hard drive. It doesn't come as a surprise: The Cheetah 15K.5 is the fastest 3.5" hard drive we've ever seen. Seagate claims up to 125 MB/s transfer rates, which our benchmark results confirm. We measured 128.6 MB/s as the maximum for sequential reads, which is a world record off the medium. The minimum transfer rate of 73 MB/s is excellent as well. But the high transfer performance comes at a cost: a 6.6 ms average access time with rotational latency is clearly behind the 5.x ms we've seen with other 15,000 RPM drives. Yet the result is still acceptable given that this is the 300 GB high-capacity version.