I purchased this Hitachi drive to upgrade from the existing 100GB 5400RPM drive in my laptop. I also ordered the Apricorn EZ-UP-UNIVERSAL EZ Upgrade Universal Notebook Hard Drive Upgrade Kit, which you will need to make an exact duplicate of your old hard drive on to the new one. The upgrade went smooth and now the old hard drive serves as a clone back-up of the new one. This Hitachi runs pretty quiet and FAST. I love it. I installed it into my *2004 HP Pavilion ZD8000 Pentium IV 3.2GH w/2GB RAM running XP Pro srv pack 3* and the increase in speed is noticeable. Startup takes about the same amount of time (even after turning off non essential services), but all other processes go much faster. Programs open in a flash. My plan was to get another two years of top performance before purchasing a Windows 7 machine and this HD makes that happen for me. I'm in love with my laptop all over again.