Slow down with NT 4.0 Server

I recently installed NT 4.0 server on a new machine with a new HDD, 15 GB 7200RPM Maxtor. Everything worked fine until I converted to NTFS, and now there is a major slow down in all applications. I have applied SP6a, but it didn’t help. I am running this on a HP Pavilion 533Mhz Cerelon, with 64 MB Ram. Worked fine until I converted to NTFS. Any ideas before I reinstall Server? Thanks