There may also exist other forms of Raid-Enhanced (RE) firmware for drives, with or without the TLER feature tagged on.

These drives differ from desktop drives in that they often have a much smaller sector Read-Ahead value/algorithm than usual, so that they perform better for server-style applications that jump all around on the disks.

The theory there is that they are often at the end of a much slower (than the drive) network connection, shared by many clients, so they'll not normally be doing large/long sequential reads.

On a desktop drive, long sequential reads (eg. application loading, or reading/writing media files) are much more common and well worth optimizing for.

Many people firmly believe that "Enterprise" and "RE" drives also have different hardware internals -- longer lasting bearings and better vibration dampening etc. This is undoubtedly true for some models, but I find it difficult to believe when comparing two otherwise identical spin-rate drives from the same manufacturer.

Cheers