Please someone Clarify this for me. WHY is Apple still underclocking the X1600 in iMacs and MBPs? I used ATItool in Windows XP and it shows both Memory and Clock speed clocked in the high 300s. This is INCREDIBLY frustrating. I can overclock safely to the stock speeds of 470/470 for an hour gaming with no heat issues. I can SORT OF understand underclocking the laptops, but the iMacs? Much less the 20-inch or 24-inchers (I have a lowly 17" iMac) which have so much room inside...... I cannot game well in Mac OS X with no overclocking tool supporting the X1600... Doom 3 runs at native res (1440x900), but only on Low settings... Even Call of Duty 2 chokes occasionally in smokey situations. Anyone else care to share their X1600 experience, or their opinion on the matter?