We can't get too excited about an adapter, but Belkin's AV360, a device that bridges the gap between a 27-inch iMac and your HDMI-based video components, has stirred our enthusiasm by meaningfully differentiating itself from its competition. The key trick of the Belkin AV360 lies in its ease-of-use. It requires less fiddling than the competing Kanex XD. It also plays better with HDMI switchers, a task that gave the Kanex model trouble. Throw in the fact that the Belkin AV360 and the Kanex XD each have a list price of $150 and our decision is easy. If you own a 27-inch iMac, and you want to pump in your cable box, your game console, or a Blu-ray player into the Mini DisplayPort input, the Belkin AV360 is the best device for the job.
We concede that these adapters will only appeal to a limited audience. Technically, they work with any display that has a Mini DisplayPort input, but their primary reason for being is to input home video components into the 27-inch iMac. It would have been far more convenient had Apple built an HDMI input into its largest iMac from the start. Perhaps the recent addition of HDMI to the Mac Mini offers hope for the next iMac update. For now, annoyingly, you'll need a specialized Mini DisplayPort-to-HDMI adapter that can convert an input signal. A standard, inexpensive Mini DisplayPort-to-HDMI output adapter won't do the job.
The Belkin AV360 is actually significantly larger than the Kanex XD. The Belkin model measures 0.875 inch high, 6.25 inches wide, and 3.375 inches deep. That's nearly three times the width of the Kanex XD. We suspect the Belkin's extra size has to do with extra internal components that provide important differences between the two adapters.
The first difference is that unlike the Kanex XD and its wall-wart power adapter, the Belkin AV360 is USB-powered. That's a minor distinction, as wall outlets are as easy to replicate as USB ports, but in the interest of minimizing cable clutter, we prefer the AV360. It keeps your desk tidier by routing the adapter's cables in only two directions, as opposed to three with the Kanex XD. The bigger advantage for the Belkin AV360 is that it simplifies the configuration steps due to its built-in resolution scaling.
The resolution scaling is important due to the limits of the iMac, which Apple only configured to handle certain resolutions through its Mini DisplayPort input. It will accept video sources in its native 2,560x1,440 pixel resolution, but it's not equipped to handle 1,920x1,080, aka 1080p. Instead, the next highest resolution is 1,280x720, or 720p.