The logic board is the next logical step. The CPU is the last to go, left clinging to the side of the heat sink via a thin smear of thermal paste.

After teasing it away with a spudger, we decipher its markings:

Quad-Core Intel Xeon E5-1620 v2 with 10 MB L3 cache, clocked at 3.7 GHz, Turbo Boost up to 3.9 GHz.

While it took a bit of a trek, a CPU upgrade appears entirely possible—and well worth it, with an alleged cost savings of $1050 for an upgrade to 12 cores.