As far as I understand it, this adapter is passive not active. You could use a passive adapter if it was only two monitors together on a graphics card. For eyefinity it is three so the adapter needs to be "active" which means it will have to be powered by a USB port. An active DP to DVI is one like this
. Although I've heard some people get a passive adapter to work, but it can be buggy, that can sometimes require a reboot. So if you aren't gaming heavily and are fine with rebooting a lot get the cheaper passive adapter. If you are gaming heavily or don't want to reboot all of the time, you will have to the more expansive active adapter. Personally it doesn't make much sense to me why there needs to be an "active" adapter and why it has to be DisplayPort at all. Does somebody know this and could it be explained?