 The TX series used 1.8-inch hard drives with most units having 512 MB of ram built into the motherboard and one RAM slot free to be upgraded to 1.5 GB of RAM max, whereas some higher-end models have 1 GB of RAM built in and so were able to be upgraded to 2 GB of RAM max.They also had an instant-on feature, which has become a common feature in notebooks since HP introduced it in their notebooks in late 2004 which lets one play DVD movies, view photos from a memory stick or SD card or play music CDs without booting up to Windows.It has different model names outside North America.