If I remember correctly, support for 'Advanced Format' has been introduced with DSM 2.3,
meaning that the NAS can format correctly the harddisk using 4k format blocks.
I remember I've seen probably on this forum some tests that were showing a sensible
performance difference for a AF-able
disk between 'old' and 'new' format.
The WDC page recommends Linux kernels 2.6.31 or newer (or better 2.6.34).
Currently DSM 3.0 beta has kernel 2.6.32 so most of the support is there,
and current DSM 2.3 should be something like 2.6.26
(see also https://ata.wiki.kernel.org/index.php/A ... nux_stands