This is a **USED** system, so a good portion of this may be settings the former owner changed.
XPS 720 H2C
QX6850 OC'd @ 3.66
2x 8800GTX 768MB (SLi)
SIW shows the cores hitting 70-75C at load (while gaming), depending on core. Idle is in the upper 40s.
Full load produces full speed on the H2C fan, which I would have expected.
Unstable after a short time at that speed/temps.
Reducing the multiplier so the CPU runs at stock 3.0 stabilized the system, but is obvuously not optimal - we went for an H2C QX endowed system for a reason.
I would like to get this back to 3.66. I'm not afraid to do some work on this, while I'm not used to Dell's hardware specifically, I'm no stranger to tearing down systems, including water-cooled (the other system in the house is a modified Voodoo Rage).
Immediate things that come to mind as possible issues are:
1) BIOS settings? This is used, so no clue what might have been changed in there. All I did was lower the multiplier. I'm not very familiar with OCing, so I wouldnt know where to begin without guidance. Just getting the BIOS to stock settings would be nice.
2) Thermal paste? If the H2C wasn't seated properly (I've seen other posts here and elsewhere suggesting this is an issue), I may need to yank it and clean the block + CPU and apply some Arctic Silver.
3) Fluid levels? No way to see it. Is there a method of checking this? Looks like Dell uses an "injection" method for filling? I wouldn't be surprised if there is a proprietary method/fluid
4) Thermoelectric failure? Pump Failure? Blockage? (read more than a few posts about there being packing material left behind inside the H2Cs) Maybe easier to simply order a replacement H2C unit? I shudder to think what that might cost me (no warranty).
EDIT: I want to point out, I've seen the TS reply to the 730 H2C random reset/reboot thread. If I could get that same exact info (BIOS settings for a 720 instead of 730), I'd expect the issue to be readily resolved.