So I've been out of the PC gaming world for a while, but recently I just wasn't satisfied with my ps3 and couldn't justify the 550 for a ps4 when my toddler kept destroying my laptops.  so I decided to get back into the desktop gaming world.
 
Built a decent box after christmas with some input from some friends and co workers.
 
intel i5 4690k devils canyon chip
MSI z97 gaming 7 board
250 SS samsung SS drive for OS
1 tb hd for normal storage
2 x 8 GB G.Skill Ripjaws X Series Ram
Rosewill 1000w power supply bronze series
Pioneer Blu Ray Burner
 
Everything was working OK, but my friends were playing Arma 3, and though I could run it, the graphics were putrid without a video card.
 
So I waited, and found, what I thought to be, a great deal.  It was a Refurbished
EVGA 02G-P4-2661-RX GeForce GTX 660 2GB 192-Bit GDDR5 PCI Express 3.0 x16 HDCP Ready SLI Support Video Card
 
Installed it.  Manually downloaded the drivers and installed.  Everything seemed fine.
 
Then the next day I started to play Arma 3, about 5 min in.. the sound is still going, but the display and everything else is hung up.
 
I tweaked a few things here and there, reading all kinds of different reasons which could cause me problems.  But I keep getting the same result.  Basically whenever the scene gets graphically intense.  everything hangs.  sometimes for 10 seconds, sometimes for a minute.
 
I'm frustrated.  Just wondering if I missed something stupid or did something wrong somewhere along the way.  Also I know it COULD be the refurbished part was problematic on arrival.  I'm just unsure and dont know how to test.  Also everything works fine with my day to day usage.  it only hangs when its being pushed.
 
Thanks in Advance for the help,
Andy

tried running 3dMark and it crashed like 10 seconds in with this error
 
Unexpected error running tests.
Workload Single init returned error message: File: device_resources.cpp
Line: 313
Function: class eva::com_ptr<struct ID3D11Buffer> __cdecl eva::d3d11::device_resources::create_buffer(const struct D3D11_BUFFER_DESC &,const struct D3D11_SUBRESOURCE_DATA *) const
Expression: hr: DX11 call failed [-2005270523].
Hardware device removed.
DXGI_ERROR_DEVICE_REMOVED: ID3D11Device::CreateBuffer:

With Precision X, try down clocking the card by say -50Mhz to -100Mhz and then run 3Dmark again. If by downclocking the card you are able to run 3Dmark without it crashing then it's most likely a hardware issue with the video card requiring an RMA. While you're at it, check the health of your power supply's +12v rail in your BIOS. You can usually access this information under PC Health Status, System Monitor or HW Monitor. The 12 volt rail should be between 11.6 ~ 12.6 volts without any fluctuations outside of 0.05v. Rapid fluctuations even within the 0.05 range would also be a cause for concern. 

I tried the downclocking thing.  I didn't know if you meant GPU or mem clock. so I turned them both down 100 Mhz.
 
Everything ran clean.  no issues.
 

checked the 12 volt rail.  it sits at 12.192V and doesn't fluctuate at all when I was watching it for a couple minutes.  Also reinstalled the drivers one more time just as you suggested.
 
The only thing that seems to help is the reduction of the clocks.  and even still, I just played a game for about an hour, at then it started getting choppy on me.