Is there any info in Event V? It may not be listed as a failure it may be listed as a error or warning, but def pay attention to the last hour or 24 hours tab. Best place to start. Usually a reset like that is because of too much/too little vcore voltage but it could be a whole list of things.

Some weird grounding with the chassis affecting the power usages compared to the open Dark bench plate?

Hoggle

GGTV-Jon
Some weird grounding with the chassis affecting the power usages compared to the open Dark bench plate?

That is kind of what I was wondering myself if something was touching the motherboard to the case besides the mounting screws it could cause problems with crashing. Thing is it would probably crash even at default speeds though if this was the case.

Thanks for tips about shorting!
 
Found flexing of motherboard near power swtches and I/O shield.
Observed VRM heat sink touching case; no other non-standoff points of contact.
Loosened all motherboard screws.
This relieved flexing of motherboard near power switches and I/O shield..
VRM heat sink no longer touching case.
Still crashed after 16 minutes (versus 6-10).
 
Reseated DIMM reseated during case install to sneak cable past.
Still crashed after 16 minutes.
 
Ran Memtest86 overnight.
Successfully passed ~3.5 passes before manually stopped.
 
System left to rest powered on for three hours.
Reran 56K test again - passed (manually cancelled after 33 minutes).
Observed core 2 usage collapse during test (see below).
 
Let rest 10-15 minutes powered on (no restart).
Reran 56K test again - crashed within 1-2 minutes.
 
Was previous result on bench fluke?
Did undoing motherboard flex really help?
 
Also, noticed problem with CPU core 2:
Core 2 always one of hottest (hottest?) cores.
Core 2 usage sometimes falls from constant 100% to variable 24-82% during test.
Core 2 Thread #1 usually, but not always less than Thread #0 (example: 72% #0, 24% #1)
All other cores stay 100% both threads.
 
In graph below, Core 2 usage change correlates with sudden decrease in CPU Package Power near end.
Prior to spike, Core 2 100% usage.
After spike to end of test (crash), Core 2 variable usage.
 
Package Power Drop Correlated With Core 2 Usage Collapse
 

 
Also observed during successful 56K 33 minute test above, but did not cause crash.
 
HWiNFO Core 2 Usage Drop During 56K 33 Minute Success Test
 

geninfo

Hoggle

GGTV-Jon
Some weird grounding with the chassis affecting the power usages compared to the open Dark bench plate?

That is kind of what I was wondering myself if something was touching the motherboard to the case besides the mounting screws it could cause problems with crashing. Thing is it would probably crash even at default speeds though if this was the case.

Thanks for tips about shorting!
 
Found flexing of motherboard near power swtches and I/O shield.
Observed VRM heat sink touching case; no other non-standoff points of contact.
Loosened all motherboard screws.
This relieved flexing of motherboard near power switches and I/O shield..
VRM heat sink no longer touching case.
Still crashed after 16 minutes (versus 6-10).
 
Reseated DIMM reseated during case install to sneak cable past.
Still crashed after 16 minutes.
 
Ran Memtest86 overnight.
Successfully passed ~3.5 passes before manually stopped.
 
System left to rest powered on for three hours.
Reran 56K test again - passed (manually cancelled after 33 minutes).
Observed core 2 usage collapse during test (see below).
 
Let rest 10-15 minutes powered on (no restart).
Reran 56K test again - crashed within 1-2 minutes.
 
Was previous result on bench fluke?
Did undoing motherboard flex really help?
 
Also, noticed problem with CPU core 2:
Core 2 always one of hottest (hottest?) cores.
Core 2 usage sometimes falls from constant 100% to variable 24-82% during test.
Core 2 Thread #1 usually, but not always less than Thread #0 (example: 72% #0, 24% #1)
All other cores stay 100% both threads.
 
In graph below, Core 2 usage change correlates with sudden decrease in CPU Package Power near end.
Prior to spike, Core 2 100% usage.
After spike to end of test (crash), Core 2 variable usage.
 
Package Power Drop Correlated With Core 2 Usage Collapse
 

 
Also observed during successful 56K 33 minute test above, but did not cause crash.
 
HWiNFO Core 2 Usage Drop During 56K 33 Minute Success Test
 

Might just be your cpu cooler mount. Either the TIM isn't quite right or the cooler is cranked on too much maybe on one corner or maybe even both. Remount with pea method, squish and twist cooler slightly while pushing down and then screw down in X pattern. Try test again.

geninfo

wmmills
 
Might just be your cpu cooler mount. Either the TIM isn't quite right or the cooler is cranked on too much maybe on one corner or maybe even both. Remount with pea method, squish and twist cooler slightly while pushing down and then screw down in X pattern. Try test again.

 
Because of insufficient cooling of the core, uneven pressure on the die, or pressure on the socket pins?
 
Core 2 and some other cores always run hotter than others even with different thermal interface applications.
Core 2 does not thermal throttle or get close to TjMax when its HWiNFO-reported usage collapses under load as above.
 

Maybe all 3?!? The flexing of the mobo really shouldn't be a issue cause the whole setup sits still while your using it, but when you moved it, say from bench to case, maybe things could move and change. Did you try what Saj said and go back to bench? Other than running default settings where you should be inputting a dialed in manual vcore/timings/command rate/no xmp etc... before you bench anything, seems power delivery/allocation may play a part judging by sudden restart with no errors logged, but that could be because of running default settings in stress benches also.

For the cpu vcore seeing what the auto starts you with and working incrementally from there is fine, unless you can dig up Intels spec sheets and go through them. The ram you use the base values set on the sticker on the side of one of the sticks, but you may want to set a command rate of 2 to start with for better stability. If your using a lot of ram, like all slots filled with high counts then you may have to raise the rams base voltage a tick to compensate. Just watch all your temps and move slowly lest you end up with a smoking pile of rubble.