My 758 replacement board showed up Thursday in good shape.  It's a 1.1.  Whew.  It had two problems out of the box:  I couldn't run my RAM at rated speed (Memtest would hang or reboot after a couple of passes) and the system temp reported in BIOS and eLeet is way out of whack (100C +- 10C).
 
After wrestling with this for a two days and spending a long time on the phone with my friends in support, I discovered that the RAM issue was caused by the BIOS version.  The sticker on the eeprom socket says SZ2W (IIRC, I can't crawl under the desk just now - maybe it's 2U) which I don't even see in the list.  What was actually installed was 74.  So much for  "replacement boards are shipped with the latest BIOS".  I downgraded to my favorite - SZ2Z - and RAM is running stable at 1600.
 
That leaves the system temp thing.  My old board ran in the 30s.  As it should.  Support doesn't see this insane temp as a problem.  To my mind, it's either the temp sensor or something is really messed up with the thermal management, like a missing pad or blob of TIM.
 
Can anyone tell me where the system temp is measured?  If it's part of the chipset (south bridge maybe?) then this board is sick enough to go back.  If it's a discrete sensor that really measures case ambient, then I can (probably) live with it.
 
It's an A1 board so I guess it's EVGA's problem long term, but I sure would like to know what's going on.
 
Thanks,
Z.

I agree that 100*C indicates something wrong, and I'm surprised support didn't agree with you.
 
Re-applying the TIM probably won't help with the system temp since the system temp is not monitoring a specific chip or heatsink, but trying to sample the ambient air beneath your video cards.
 
Here is a picture I made showing the system temp sensor location on my board, it should be located in a similar position on your board, between the PCI Express slots.
 

 
The sensor may be standing slightly above the board on very short legs.
 
If you can test it outside of the case and blow some air on it and see how the temps change (or not as the case may be), that should give you the leverage you need with support.

You're welcome, glad to be of some help.
 
I'm pretty sure any celsius/fahrenheit conversions are done elsewhere, the sensor basically alters it's resistance based on temperature. Another chip (for example the Fintek chip which also handles smart fan and other duties) does the conversions to a numerical value, then it's up to the BIOS/software to display it in celsius/fahrenheit.
 
Referring back to my picture above, the Fintek chip is the large rectangular chip to the far left of the sensor above the two left-most PCI Express slots.
 
I'd lean more towards suspecting a faulty sensor than being stuck sending Fahrenheit instead of Celsius.

I haven't read through "The Truth..." yet but now I have to ask, is the system temp informational only?
 
Is there a monitor feature somewhere that might shut down the system (suddenly!) based on an (incorrect)  high reported system temp?
 
Z.