Seagate Technology has begun shipments of its first ever 3.5-inch drives utilizing the Perpendicular Magnetic Recording method. Seagate's announcement came earlier today with the introduction of the Cheetah 15K.5 enterprise class hard drives which feature a 15,000RPM spindle speed and capacities of 73GB, 146GB and 300GB.

The platter density has been doubled compared to the 15K.4 line of drives effectively reducing the number of platters and heads by 50%. The 300GB model will feature a 4-platter design using 8 heads, the 146GB model will use 2 platters with 4 heads and the 73GB drive will utilize a single platter with 2 heads. All three models will come in Fibre-Channel, Ultra320 SCSI, and Serial Attached Storage interfaces at 400MB/sec, 320MB/sec, and 300MB/sec respectively. They will feature a low 2ms latency and a 3.5ms average seek time which matches the older 15K.4 line.

What has changed is the performance with a great increase in transfer rates over the 15K.4 line. The sustained transfer rates have increased an average of 15-29MB/sec across all models with the help of the perpendicular nature of the bits as well as the increased 16MB drive buffers.

Power consumption has also dropped by up to 2 watts in some models; mainly the Serial Attached Storage versions of the Cheetah 15K.5.

The Cheetah 15K.5 has begun shipping to OEM customers, according to the press release, and is expected to distribution channels later this quarter. Seagate first introduced Perpendicular Magnetic Recording in its Momentus 5400.3 series of notebook drives in mid-January which brought 160GB of capacity in a 2.5-inch form factor. Speaking with our contact at Seagate, they had mentioned that we should see desktop drives utilizing the PMR method hit the market by this summer.