I am looking to get an Apple Mac Pro - Quad Core - One 2.8GHz Quad-Core “Nehalem” Xeon in the next few weeks with the ATI Radeon HD5770 Graphics with 1GB ram graphics card.

I have notice a few people on here who have Macs have experienced display issues with Houdini. I was wondering if there were any known issues with this card and Mac configuration.

Macs with recent ATI cards are fine. It's Nvidia hardware on Macs that have a few issues, but they have been worked around in Houdini so you shouldn't notice them, other than the fact that a couple of features are disabled.

Edit: Note that there are some issues with ATI cards on Linux/Windows, if you decide that you want to dual boot the Mac. There is a current issue with incorrectly facing normals in Catalyst 11.2, and selection takes a bit of tweaking of an ATI profile file to get running quickly.

Thanks for that most useful to know.