What is 'CPU' memory?

[tparker <tparker@xxxxxxxxxxxxxx>]

When playing WoW through Wine (1.3.6) my video settings are limited 
because some of them require "2G or more CPU memory".  Another computer 
in the house can play in Windows with those settings maxed out on a 
graphics card that only has 1G built in, so the setting doesn't mean 
graphics memory. My computer has 5G of ram (32 bit PAE kernel) so it's 
not that. So what is CPU memory and how do I tell if I really don't have 
enough or if there is a problem with the game detecting it properly 
through wine?