That's the trouble with hard drives in retail boxes, you don't know for sure what you're getting until you open it up. There seems to be very little about this drive anywhere online. There used to be a WD10EADS (1TB) and a WD20EADS (2TB), and I've got some of the 20EADS that I've been using in computers with no problems so far. I'm guessing this is the successor to the 10EADS, only 6Gb/s instead of 3, although unlike the EADS line it may be "advanced format". The 20EARS is AF, and lots of people here seem to have used them in TiVos successfully. Best Buy currently has a 1TB Seagate on sale for $40 less. It's a 7200 rpm drive, whereas yours is a 5200 or 5900 or whatever those "green" drives run at, so I'd expect the WD to be quieter and cooler, though maybe the noise part isn't that great a difference. Technically the EADX doesn't meet the specs Best Buy has listed for the WDBAAY0010HNC-NRSN ('cause it exceeds them) if you want a reason to return it. Does the box have a sticker saying anything about cache size? Does it actually say WDBAAY0010HNC-NRSN on the bottom? Is there anything on the sticker on top of the drive about "advanced format" or special things that need doing to use it with Windows XP? That EADX should probably work okay in a TiVo, as long as intellipark can be disabled with wdidle3. Did you order this from Best Buy online, or pick it up at one of their stores?