CPU cooler replacement and shroud mod on X51 R2 : r/Alienware
PGRP5 - Dell PGRP5 system board lga1150 w/o cpu alienware x51 r2 andromeda - serverevolution.com
Digital Foundry vs. the Alienware X51 R2 | Eurogamer.net
Old & New (Bring Alienware X51 R2 back to life) by meng8123 - Intel Core i7-4770, GeForce GTX 970, EVGA Hadron Mini ITX Tower w/500 W Power Supply - PCPartPicker
X51 R2 CPU Cooler Upgrade and GTX 970 Success - Dell Community
Alienware X51 R2/R3 CPU Replacement - iFixit Repair Guide