Just now, I tried folding for the 20th attempt and now getting constant power off and power on cycling with no screen or post.  I think my PSU just gave but what are you guys thinking?  I unfortunately don't have another PSU to test the rig without taking apart my main rig which will not happen.  (80lbs+ custom cooling)

Test the next time this happen by Turing Off your Monitor and pull the Power Cable from your Monitor.
Wait a minute and plug the Monitor Power Cable back in and Turn on your Monitor and is should come back on.
For me this has worked 10 out of 10 times while Folding. Also this is when your KB still works by turning on and off the "Num Lock" Key.

I'm curious about the conclusion of this. I don't have a spare PSU anymore, wish I did. It sounds like you have had this issue before. Hope it's something easy.  

Just ordered this bad boy.  I know its a bit of pay and extreme some might say but its more of a long term investment (12-year warranty) for anything I throw at it and can be a backup PSU in emergency situations for my main rig as well. 

HK-Steve

GTXJackBauer
Just ordered this bad boy.  I know its a bit of pay and extreme some might say but its more of a long term investment (12-year warranty) for anything I throw at it and can be a backup PSU in emergency situations for my main rig as well. 

Wow, that is a good warrantee time.
Fingerscrossed it solves your problem...

I hope so too m8.  

I did some comparisons and read some reviews.  I know Platinum would have been cheaper but since I knew I would run this PSU around the clock for years to come, I didn't want to cheap out and just go with the best design, components and efficiency possible.  I would have liked going to a higher wattage in case I ever have two beefy machines running high end GPUs but I feel 850w for the secondary/folding rig is more than enough for SLI, even with custom cooling if I ever head that route.  Just worry about the spikes one could get during benching, etc. but I'm not a huge bencher so I'm not too worried there.  
 
I will say, the two Titanium 850w PSUs in the market is this Seasonic and EVGA's.  After looking, Seasonic has more connectors and is cheaper in price while scoring a tide better in reviews so it was a win/win all around.  The only issue I might have is the CS as I feel is a tad better with EVGA because I've read how much people had to pay to ship their RMAs to Seasonic etc., as it didn't sound like a friendly price but also read how they've gone above and beyond for some as well.  I just hope I'll never have to RMA period.
 
I should note, some of the Seasonic PRIME PSU retail boxes advertise 10 years of warranty on them while earlier this year, Seasonic had announced it changed their policy and extended it from 10 to 12 years while the competitors are still at 10.      To put this into perspective, this PSU that was purchased today is insured till 2029.  
 
For those that might be interesting, here's a nice review on this PSU.

How are your GPUs cooled ?
 
If air cooled, what happens when running only 1 GPU folding ?
 
Have a spare video cable to test with ?
 
Monitor input select set to:  Auto or Manual ?
 
Your OP mentions "SLI" --> you have SLI disabled for Folding - right ?
 
Usually a bad PSU on too high of a load just turns off the PC
 
Any issues in Device manager ?
 
More than 1 sound driver loaded (MB + Nvidia or sound card) --> if so delete all but One sound driver
 
Run CCleaner  (free version) - clean up your drive, then run the Registry tool

PSU showed much quicker than I thought.  Distribution center next state over had the PSU so it was a win/win other than Fedex taking their time instead of coming literally the next day of purchase.  Regardless, took out the non-modular PSU out (gasp) and put this bad boy in the Antec 1200.  Started up folding and now for some silly reason, I can't get advanced control to open for the life of me.  Uninstalled, restart, installed, restart, still no show.  I don't know what else do to.  I did remove a headphone driver only if I bring over my headset to it which is rare but that didn't change a thing.  

I feel I'm all out of options here.  Hope some have some good recommendations or advice on what I should do.  I would love to steer away from a complete format if this is possible.  Thx