>i always defrag my system partiton to have EXE and DLL files on outer tracks of HD so seeking is smallest and MFT is close to outer tracks too, without prefetch this is fast, but with prefetch its double the seek/acces Cylinder zero is closest to the centre of the disk, so I think you want to put your dll's on the inside. VMS whose file system was used as a start for NTFS always had the MFT in the centre of the disk to reduce seeking. Then you cluster your exe's and dll's close to the centre. Derek