The rotational speed of the 4GB's platter, at 3600rpm, is the same as the 1GB model, as is the use of both sides of its internal disc platter to store data (the 2GB model uses a single side only). Aereal density has increased, however, from 15.2Gbits/inch2 to 56.5Gbits/inch2, which means the amount of data that the drive can hold jumps from about 1028MB for the 1GB Microdrive to about 3906MB for the 4GB model. Simply put, the bits are closer together on the 4GB's platter, which means the drive can hold more bits in total. The net effect is a higher capacity drive.
More bits in the same space, along with other refinements, also means greater throughput. Maximum sustained write speed jumps from 4.2MB/sec with the 1GB to 7.2MB/sec with the 4GB, says HGST. In our testing, this translated into quicker transfer rates in the real world too, though performance varies greatly with the device being used to evaluate the Microdrive.
Let's start with the good news: the Hitachi 4GB Microdrive tops the write speed ranks in the DCS Pro 14n. Kodak cameras have a history of eeking out good performance from the Microdrive line, and the 14n-4GB Microdrive combo is no exception. We recorded a throughput of 3152K/sec, ahead of the Lexar 1GB 40X WA at 3140K/sec, the previous 14n speed leader, and 2653K/sec for the 1GB Microdrive.
These numbers are generated using the test method devised for the CompactFlash Performance Database. The 14n has its own write speed measurement tool, which appears to use a different measurement method. It calculates throughput of 4.6 to 4.9MB/sec for the 4GB Microdrive, compared to a constant 4.5MB/sec for the Lexar 1GB 40X WA.
The results in other cameras aren't as stellar. Any CompactFlash card with a capacity greater than about 2GB intended for use in a digital camera must be FAT32-formatted or the full capacity of the drive won't be realized. Not all cameras can read from and write to a card that has been prepped FAT32, and of those that do, not all are optimized for this FAT variant.
The lack of optimization manifests itself in glacially slow write times. The 4GB Microdrive is at or near the bottom of the write speed rankings in the Canon EOS 10D and EOS Digital Rebel, and well back of the speed leaders in the Canon EOS-1Ds and Nikon D100. Like the Lexar 4GB 40X WA, which also requires FAT32 formatting, the 4GB Microdrive is not a card you'll select for breathtaking performance in many of the current FAT32-capable digital SLR cameras, owing mostly to performance limitations in the cameras themselves. Of the 5 FAT32-capable cameras we tested, only the DCS Pro 14n came close to delivering on the 4GB Microdrive's performance potential.
We also tested card-to-computer transfer rates. The 4GB Microdrive was firmly middle of the road, trailing the fastest flash memory CompactFlash cards by a significant margin. For example, the Sandisk Extreme 1GB manages an average throughput of 9542K/second when transferring about 225MB of Nikon D1X JPEG and NEF files to our reference PC through a Microtech FireWire CameraMate reader. The 4GB Microdrive records 3965K/sec in the same test; the 1GB Microdrive, 3222K/sec.
We measured a similar performance spread between the 4GB Microdrive and Sandisk Extreme 1GB with an Addonics Pocket Ultra Digidrive USB 2.0 card reader on the PC, and with either reader connected to a G5 1.8GHz Mac running OS X 10.3. The 4GB Microdrive is quicker than the 1GB model that precedes it, but it doesn't keep pace with the brisk card-to-computer transfer rates of top-tier flash memory CompactFlash cards.