The Socket A version of Sempron is a Tbred B core but running at 166 Mhz FSB, like one of the XP2600+ models did.
AMD lost their collective mind with the Sempron PR numbering (IMO). While the 2 Ghz Tbred B was designated XP2400+ the 2 Ghz Sempron is designated XP2800+. Yet the old XP2600+ (333) mentioned above ran at (12.5 x 166.6) 2.083 Ghz and the XP2600+ (266) ran at (16 x 133.3, I think) 2.133 Ghz.
So why is the Sempron running at 2 Ghz designated XP2800+ while two earlier 2.083 Ghz and 2.133 Ghz processors were designated XP2600+ if they are all the exact same core? You got me!
In theory, the Sempron should overclock just as well as the old Tbred B's which typically topped out at about 2.3-2.4 Ghz with good air cooling and voltage mods. However, AMD Socket A processors are all now permanently locked (except the mobiles) and you have to overclock by FSB increases alone.
<b>56K, slow and steady does not win the race on internet!</b>