water

[ituneman]

Hi,
i recently bought a new laptop a dell xps 15 with a 2048MB NVIDIA® GeForce® GT540M video card, I installed WoW but it still has 5GB to go so i started playing it. I play it on ultra still at about 50fps which is good and it was working fine until I tryed to swim or came across some water it just simply wasn't but when i swim the water comes back
why is this and is there anyway i could fix it?
thanks