Given the subject of this post, this has been happening for about six months now. I would really appreciate it if someone could provide me with some new ideas. 
 
Setup info:
I have dual monitors, and play the game in borderless windowed.
This only happens when playing ffxiv. It's probably the most graphic intensive game I play, though.
This only happens when SLI is enabled. 
I have two GTX 570's, one purchased in 2011, one in 2013. 
i7-4790k
16GB RAM
Res: 1920x1080, 60Hz
Windows 8.1 Pro
Current driver: 353.38, though like I said it's been happening for awhile, so I've been through a few drivers.
I always do a clean boot.
I always do a clean install of drivers, and have Nvidia audio drivers disabled.

Things I've tried:
Changing settings. It happens whether set to min or max. Crashes after about an hour, sometimes less.
Switching card positions on mobo.
Seems to happen more often when I swap window focus, so I've tried just playing the game and not using Chrome or anything, but it still happens. 
Like I said it only happens when SLI'ed, can go all day without a crash when SLI is disabled. 
When I tried playing fullscreen, every other frame lost all red and green colors. So it was bluescale (like greyscale, but blue). Idk how else to describe it lol. 
Tried using a different SLI bridge, and tried both bridge ports on the cards.
 
So yeah, it's kinda weird. I'm thinking it's something going bad on my older card. Though when I bought the 2nd card, it died within 60 days and they sent me a refurbished replacement, so I suppose it could be that one too. I'm hoping it's not hardware though, which is why I thought I'd ask here. Thanks in advance for any help. 
 

I've tried both places on the cards, but I never thought about the bridge itself being bad. I have like 3 so I'll replace it and post results tomorrow. Thanks!

Hah. And er, actually I had more time than I thought so I went ahead and not only switched out the bridge but tried the other spot as well. Same symptoms persist. :(

I blow them out like once a year. For the first two years they stayed around 90, but since then I keep them about 70. So unless the first small case I had did some damage that I'm seeing now. 

But actually, just to be sure I've now changed to a 3rd SLI bridge (this one is actually EVGA too) and haven't had a crash in about two hours. Doesn't mean anything yet, but I'm hoping.
 
Edit: Nope, crashed D:

Well the game's been fine the last 3 years, until last Christmas (-ish). I've searched forums and while some other people have crash issues too, they usually find a solution (which doesn't work for me). 
 
Trying .38 now, thanks. 
 
Edit: Seems to happen a little less often with this driver, but still crashing.