GTX 770 sli overclock benchmarks? Answer fast please

Axzevos

Honorable
Jun 12, 2013
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10,980
So yeah. Whats safe benchmarks to overclock my gtx 770 sli for? My system are:

Corsair TX 850W PSU
Intel Core i5-4670K
MSI Z87-G45 Gaming, Socket-1150
Cooler Master Seidon 120M
Crucial DDR3 BallistiX Sport 16GB KIT
Gigabyte GeForce GTX 770 2GB PhysX CUDA
Gigabyte GeForce GTX 770 2GB PhysX CUDA
Kingston SSDNow V300 120GB
WD Desktop Blue 1TB SATA

What will it for me be 100% safe to overclock the cards to?