From one of Syar2003's links I got this. Author: Ryszard
Given a wafer of say 50 R350 cores, a random selection of those (maybe 10% say) will be tested for defects. Should all the tested cores check out fine, that wafer of cores is marked as fine and all the cores are then used to produce full Radeon 9800 Pro products. Should any of the random test sample fail the testing, the wafer is to be discarded completely (if all selected cores fail initial testing), or used in 9800SE products with 4 pipelines disabled. The second scenario is more desirable, since it means that ATI get to make use of cores that may be slightly defective, but not entirely so.
It also has the statistical advantage that some cores on the defective wafer may be perfectly fine, with all 8 pixel pipelines able to work correctly, essentially giving rise to fully working R350 cores sold as cut down 9800SE's. With final QA testing done by the board manufacturer, after it purchases packaged wafers from ATI (produced by TSMC), any completely defective cores are discarded at that point in production (a statistically small amount). This lets fully working R350 cores slip through the cracks as 9800SE's, which are then sold accordingly, at an attractive price point befitting a mid-range entrant, to consumers.
We then have the softmod scenario, where fully working cores can then have their 4 'defective' pixel pipes enabled by the card driver, giving you free performance.
I am guessing that if you get the 9800SE- AIW, you could get lucky and get one that can have the 4 other pipes enabled? That is only if you get lucky though. Making it a 9800PRO. Did I read that Right?