Given the fact it crams in two chips, it should come as no surprise that the HD 4870 X2 is a whopper of a graphics card. At 270mm long, it is one of the longest graphics cards you can buy, though notably it's only the same length as an nVidia GTX 280, a card which uses just one chip.
Probably the most striking thing about this card, though, is it's weight. This has been something of a trend with ATI's recent cards and is something we still haven't got to the bottom of yet - for some reason nVidia is able to make its stock coolers considerably lighter than ATI's. Not that this should be of much concern if you make sure the card is securely held in your case.
The cooler itself is a fairly typical design with a large centrifugal fan sucking in air from the front, blowing it across the heatsinks over the chips and exhausting it out the back. It works well, staying consistently quiet when not gaming and although very audible when going at full pelt, we would expect you to be wearing headphones at such points. Our only concern would be the same worry we had about the HD 4870 and HD 4850 cards. Namely, they do run very hot. Obviously ATI feels this isn't to the detriment of the card and indeed we suffered no stability problems but you'll need a very well ventilated case if you want one of these cards.
Taking a tour round the card we see the two auxiliary power connections along the top edge towards the back of the card. ATI has again chosen to mount these connectors perpendicular to the PCB, which we feel makes them more difficult to access than the conventional upwards facing connectors.
Due to its massive power draw, both connectors must be used for the card to even run. In fact at full pelt the card pulls a colossal 285 Watts so you'll be wanting at least a 600W power supply to keep this card going.
Output options are par for the course with a multi-output analogue socket nestled between two dual-link DVI outputs. The DVI sockets can be used in conjunction with DVI-to-HDMI and DVI-to-VGA converters and the former will allow you to pass a digital audio signal out to your TV or AV setup. Meanwhile the analogue connection support S-Video natively along with component and composite with the help of a provided dongle.