Silent Systems' SilentDrive is a foam and polymer slip cover that wraps over 3.5in drives to almost halve noise from 40 decibels to 24 decibels. That's about the level of home equipment like TVs, VCRs and phones. Chassis vibration - another key noise source - is also cut by up to 70 percent. Already patented by Silent Systems and licensed to BIOS specialist Phoenix Technologies, the company sees cutting out the racket as a key component in making the perfect home PC. And it's not just the irritation factor that counts, according to Silent. Noise can also negatively affect communications and multimedia hardware. "As PCs move from the office to the living room, PC manufacturers are investing heavily in value-added features such as stereo, telephony and television capabilities," company president Greg Wyler told an audience at the recent Windows Hardware Engineering Conference. "The noise from whining hard drives and fans is a major impediment to PCs reaching this potential market. SilentDrive helps eliminate PC noise, making the PC an appliance as quiet as a VCR." Phoenix has also licensed Silent's technology for intelligently analysing a PC's thermal activity and suggesting fan speeds and system positioning to ensure that fans aren't running at a noisier level than is required.