Here are some options:
F886J Yorkfield Quad Core, Q9550, 2.83G, 12MB, 1333FSB, E0
N650J Yorkfield Quad Core, Q9400, 2.66G, 6MB, 1333FSB, R0
D923J Wolfdale Dual Core, E8500, 3.16G, 6MB, 1333FSB, 65W, E0
Y934C Wolfdale Dual Core, E8500, 3.16G, 6MB, 1333FSB, 65W, C0
Y935C Wolfdale Dual Core, E8400, 3.0G, 6MB, 1333FSB, 65W, C0
H399J Wolfdale Dual Core, E8400, 3.0G, 6MB, 1333FSB, 65W, E0
K905F Wolfdale Dual Core, E8300, 2.83G, 6MB, 1333FSB, 65W, C0
Y932C Wolfdale Dual Core, E8200, 2.66G, 6MB, 1333FSB, 65W, C0
Y442H Wolfdale Dual Core, E7300, 2.66, 3MB, 65W,M0
MP628 Conroe Kit, E6850, 3.0G, 4MB, 1333FSB, G0
MP162 Conroe Kit, E6750, 2.66G, 4MB, 1333FSB, G0
PN416 Conroe Kit, E6700, 2.66G, 4MB, 1066FSB, B2
KU345 Conroe Kit, E6600, 2.4G, 4MB, 1066FSB, B2
MP160 Conroe Kit, E6550, 2.33G, 4MB, 1333FSB
DX484 Conroe Kit, E6420, 2.13G, 4MB, 1066FSB, B2
DX485 Conroe Kit, E6320, 1.86G, 4MB, 1066FSB, B2
Y933C Conroe Kit, E4700, 2.6G, 2MB, 800FSB, G0
CY593 Conroe Kit, E4600, 2.4G, 2MB, 800FSB, M0
MP159 Conroe Kit, E4500, 2.20G, 2MB, 800FSB, M0
DX483 Conroe Kit, E4400, 2.00G, 2MB, 800FSB, L2
RX522 Conroe Kit, E4400, 2.00G, 2MB, 800FSB, M0
HU587 Conroe kit, E4300, 1.8G, 2MB, 800FSB, L2
RX391 Conroe Kit, E2180, 2.0G, 1MB, 800FSB, M0
YU563 Conroe Kit, E2160, 1.8G, 1MB, 800FSB, M0
XT481 Conroe Kit, E2160, 1.8G, 1MB, 800FSB, L2
XT482 Conroe Kit, E2140, 1.6G, 1MB, 800FSB, L2
YU562 Conroe Kit, E2140, 1.6G, 1MB, 800FSB, M0
XT483 Celeron Kit, 440, 2.0G, 512KB, 800FSB, A1
XT484 Celeron Kit, 430, 1.8G, 512KB, 800FSB, A1
XT485 Celeron Kit, 420, 1.6G, 512KB, 800FSB, A1
Y931C Pentium Conroe Kit, E2200, 2.20G, 1MB, 800FSB, M0
Edit: Just wanted to say that I copied this from the dell forums.