AIW Radeon, Retail vs OEM?

Dunno about bundled soft (always considered it irrelevant), but it'll certainly be lower clocked. Considerably so. Also, using lower grade memory. AFAIK, it's not a matter of "sometimes", but of a marketing policy : units that failed operating at higher frequencies are sold as OEM version.

But then again, you end up with an age old price vs performace dilemma : pay more to get more? Or pay less to get squat? You call the shots. Try looking around 3D graphics reviews sites for more specific benchmarks results - they often state how the card was clocked when tested.