Took me awhile to find this but here it is, "For starters, there must be an understanding of OEM or ?white box? products versus retail products. An OEM or ?white box? product is one that, as the name implies, is used by an OEM such as Dell, Micron or any other such manufacturers, in their systems. A retail product is one that you?ll find on the shelves of retail stores, such as Fry?s Electronics, CompUSA, Best Buy and other such stores. Historically, OEM products have always required a bit more care since often times OEM versions of retail products carry slight differences. These differences can range from simple things such as not having any software bundles or not having any TV output, to much more serious issues such as different memory configurations or lower operating frequencies. The latter happens to be the case with ATI?s Radeon line.We mentioned earlier that the Radeon operates at up to 183MHz. The reason for the ?up to? disclaimer is simple, only the retail versions of the Radeon (cards you can find in retail stores) run at 183MHz, the rest run at 166MHz. This means that all OEM or ?white box? Radeon cards run at 166MHz.
Things get even more confusing once you take into account the different memory configurations available on Radeon based cards. The retail 64MB Radeon cards, which are only available with DDR SDRAM, run at a 183MHz core clock as well as a 183MHz memory clock (the Radeon core is clocked synchronously with the memory clock, so the two frequencies must be identically clocked). However, as we just mentioned, all OEM Radeons run at 166MHz, which means that the OEM 64MB Radeon DDR runs at 166/166MHz (core/mem). With the same exact card running at 183/183MHz in the retail box, you can start to see why there would be some confusion here.
The 32MB Radeon cards are much easier to deal with since all 32MB Radeons, OEM and retail, run at 166/166MHz (core/mem). This includes the 32MB All-in-Wonder Radeon cards as well.
And using that information it?s pretty easy to guess that the Radeon SDR, which is a 32MB only card, runs at 166/166MHz (core/mem). It also happens to be that the Radeon SDR will be sold as an OEM card only." if you don't beleve me here is the link
http://www.anandtech.com/showdoc.html?i=1334&p=2