That's a good question... it's a heavy machine, which is typical of Polaris... 461 lbs dry. Still, I would think it'd be faster than a Yamaha Warrior, wouldn't it? If so, then it should do pretty well on the dunes.
Two friends of mine have Warriors and they will go most anywhere on Sand Mountain that you could want, as long as you choose the right line.
Also, a set of sand paddles would probably help a lot. I'd suggest a set of lightweight v-blades, with fairly short blades. No more than 7 paddle blades per tire though. They'll help a lot because you'll be able to float on the sand more.
Rob