The ultra/ultimate could just have different clock speeds, or maybe a good bundle. Check into the manufacturer if you're interested. If not, get the 128mb version, the extra 128 found in the 256 is UTTERLY WORTHLESS in a midrange card.
These days, no matter what company you like, be it <b>nVidia, ATi, or whatever,</b> no matter how logical your reasons, you're labeled an <b>idiot</b> or a <b>fanboy</b>, or <b>both.</b>