make sure your heatsink is seated properly on the gpu and if that's OK, flash your gpu to a different clock setting and if that doesn't work it might be D.O.A.
I dont think its going to work because the mobo chipset works at 533 and 667mhz. It would have to run at 800mhz to be able to do the pinmod. The reason it worked with the older dothan Pentium's is because the chipset ran at 400 and...
There is a new core duo processor with a 533mhz fsb that is clocked at 1.73 (T2250). If you changed the fsb to 667 which the mobo will support you could have a 2.16 proc for cheap!!!! They have it available on the new dell 1705's.