DS2300 10k vs 15k

[Michael D. Stricklin]

Is it possible to replace a 18gig 15k drive with a 10k ST318203LC 18gb drive inside the DS2300 enclosure.

[Luk Vandenbussche]

Check partsurfer.hp.com

To see if it is compatible

[e4services]

The drive rotational speed is transparent to the enclosure and the controller that it is connected to. It only effects the speed at which the drive itself can read and write data to the platter. But note, that this will induce 'wait states' for the completion of the read or write operation requested by the controller.
Also, the 203LC is quite an old drive, in Seagate family terms, not even the last 18GB model produced (18 and 36GB 10K drives are no longer produced since data density increases produce 73GB on a single platter). Do you really want to put an older disk in with 15Ks?