If you've been reading TR for any time at all, you know all of the caveats that go along with a multi-GPU graphics card like the Radeon HD 4870 X2. Without proper support in the game or a profile in the video driver, you may only see about half of the performance potential of your video card. There's no getting around that. But in the case of this particular card, even if the worst happens, you're falling back on the performance of one of the fastest GPUs around in the Radeon HD 4870. Not only that, but AMD's seamless dual-monitor support really makes the X2 a more attractive product than it might otherwise be. It's easily the quickest "single" video card you can buy, and it almost feels like a good deal at $549. You're really getting all the video card you need for most any game, and it occupies only one PCIe x16 slot (plus a spare adjacent slot, of course). Contrary to its protestations, Nvidia has no real answer for this beast.
Now, whether you should spend $549 on a graphics card is up to you. Personally, I think you could probably stand to put away a little more in your 401K plan or maybe save up for college, but hey, whatever floats your boat. I think we can say that buying more than two GPUs for use in your own system is pretty much a waste, though, no matter your financial outlook. Many times, we found that two GPUs were faster than three, and rarely did we find a game that really needed more than two GPUs. However, if you want the absolute ultimate graphics subsystem, you'll find it in a pair of Radeon HD 4870 X2 cards, which unspooled a fluid ribbon of track in front of us in GRID at over 100 FPS at 2560x1600 resolution. Now, that same system pulled over 750W at the wall socket, but in return it gave us GRID bliss. And it's a lot cheaper than buying a Porsche.