Synology's J series of DiskStation NAS are aimed at the value end of the market. The latest 4-bay addition to the range is the DS418j, which takes over from the DS416j and is marketed as an entry-level 4-bay NAS for home data backup and multimedia streaming.
Slow computer got you down? Maybe a hardware upgrade should be in your cards, if so this guide to the Fundamentals of Upgrading a PC is an invaluable read. PCSTATS Tips