We've already talked a little about HyperMemory, but hopefully, this article will shed some more light on what exactly it is and how ATI implements it in the latest version of their driver. The addition of HyperMemory to all drivers is essentially an all-around good thing, although it will benefit some more than others. Ultimately, we'll tell you exactly who will be very pleased, or just mildly pleased (or indifferent) with the results. But first, let's talk a little bit about HyperMemory.
HyperMemory is essentially a memory management system. Put very simply, it's meant to extend the apparent memory capacity of a card by transferring data into the system RAM if needed. This is similar to the way Windows sometimes pages data in system RAM to the hard drive when more space is needed.
AnandTech
AnandTech