Quote Originally Posted by knopflerbruce View Post
They do overclock alot worse than regular desktop chips, though. I ran them folding stable at 3.6GHz/1.15v for a long time (hot summer days included), but going higher was difficult - mostly because of the insane power draw (1250W, but peaks at 1300W+, causing my EPS cables to melt...). I have a feeling 4 GHz could be possible, unless something self ignites at 1.4+v :p Need a PAIR of ax1500i's for that project... Some PROPER EPS cables, and I wish I could add one more EPS connector to the board The free "slot" is not for power, someone at SM said when I asked if this was possible.
As you say, there is a power supply problem. The CPUs themselves seem capable of the higher speeds, but limitations with the power supply itself and with the VRMs on a server board that were never intended to push that much current are the limiting factor. You are running four CPUs...running a dual CPU system shouldn't draw nearly as much power through the EPS cables and this issue should be far less of a concern than with a quad configuration. For those who want to run one high core count CPU on a Rampage V Extreme-caliber board, a highly overclocked 18-core wouldn't be a real problem for the board or it's power delivery system (as long as a decent power supply is used). While the CPU won't break any clock speed records, it should still be able to get with a few hundred MHz of a chip with fewer cores (I'm guessing at around 4GHz for an 18-core CPU while maintaining decent power draw levels and thermals).

My $0.02....