For what it is worth: I have two 120 GB ATA/IDE HDs in my G4 Quicksilver. One is a Seagate Barracuda, and it is running at 118.4ºF at the moment, according to a freeware Utility called "Temperature Monitor." The boot drive is a 120 GB Samsung, and it is running at 102.2ºF at the moment, though typically it runs below 100ºF (sustained disk activity makes them run hotter). The Samsung boot drive is actually UNDER the Seagate, so the Seagate gets more of the benefit of cooling from the fan which is just above and perpendicular to it. Well . . . the Samsung just dropped down to 98.6ºF , and the Seagate to 116.6ºF. I joined this list because I had just bought my wife an iMac G5, and I wanted to keep up with G5 and iMac issues. I have not installed Temperature Monitor in the iMac yet, but I noted that it came with a 160 GB SATA Western Digital drive. I keep an 80 GB Samsung in an external Firewire enclosure connected to the iMac, and I have ChronoSync set up to back up all her user folders that change (e.g. mail, pictures, music) early each morning to the external drive (which is also bootable with the latest system stuff on it). I used to like Maxtors, until I fried three in a row on one of our Cubes many years ago. Similarly, an IBM Deathstar fried itself. So, for a while, I would use only the Seagate Barracudas. That is until the Samsungs came out. Now, those are all that I order (from newegg.com, by the way). --Steve (Mac user since 1988) P.S., the Seagate is now back up to 118.4ºF, and the Samsung is at 102.2ºF. No action that I know of (unless Spotlight indexing) on the Seagate, so maybe the Samsung underneath it is heating it up a bit.