Hey guys I'm seeking for some advice on overclocking my 780 ti. Recently I bought a new rad to fix my temps and reduced them to 56-57C on load and gpu does not go above 61C even at benchmarks...Its a intel 4770k Haswell and since its a very hot cpu I am not too worried. I am starting to test overclocking for a second time with this new set up. Without changing voltages I started with Memclock up to +150 for no improvement...some posts adviced to start there since you might get some improvements without changing gpu clock.
 
Now I started increasing the gpu clock +50, +70, +80 with the latest gaining about 3 fps and getting 1618 score (a 70 gain in score compared to no OC) and at +90 and +85 I get black screens using Heavens Benchmark. I tried raising the Mem Clocks +50 and +100 (with +85 and +90 gpu clocks each) and still I get black screen and windows message that Heavens Benchmark has stopped working after I press Esc when the black screen comes....
 
Could you guide me through the next step?  Should I raise Mem clock more with the Gpu clock increases? When comparing to other results it seems I got the low end on the lottery ticket without raising voltages (I still love the card anyways) but I want to overclock more since I am also playing with downsampling...especially with Diablo 3 which I can see a lot of difference and Im thinking of gettin a 120Hz Monitor, and I want my card to run as smoothly as possible to really get the most out of it. I am a beginner overclocking but don't hesitate to throw me complicated stuff...It may be my first build but no pain no gain right?
 
Set up
-i7 4770k Haswell
-Asus Maximus Formula VI
-EVGA GeForce GTX 780 Ti Dual  w/ EVGA Hydro Copper Cooler
-Ram Corsair Vengeance x2 8
-Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive
-Asus DRW-24B1ST/BLK/B/AS
(Later will  Blue Ray Burner)
-Corsair hx1000w  power supply
-Phantom 820 Case

Water Cooling
-XSPC Raystorm CPU Waterblock - Intel
-XSPC RX240 Dual-Fan Radiator V3 - Black (bottom)
-XSPC AX360 - Black (top)
-FrozenQ Liquid  V Series 250 mm Reservoir w/ Side Ports
-Swiftech MCP655™ Series 12 VDC Water Pumps - With Speed Control
-x10 CM JetFlo 120mm in push/pull config for both rads
-x1 Noctua NF-S12B FLX outflow (back)
-x1 NZXT 240mm inflow (front)

The way I approach overclocking with Kepler is to start with the GPU clock speeds.  I work with +25 increments until I get a crash.  From there I back down 5 MHz until I find a stable clock speed.  From there I'll set the clocks to default and overclock the memory in +50 increments until instability or artificating occurs.  I will back down 10 Mhz until I am stable again.
 
Now that you know your max GPU core speed and memory speed you will combine the two, which will most likely result in a crash.  At this point you're going to have to decide whether you want to sacrifice GPU core speed or memory speed (I always down clock my memory), and you should be able to reach your max stable overclock.
 
Your GPU temps looked good to me.

Temps I think are fine considering im running the RX240 fans at 1600 with the silent adapter and the AX360 fans get to around 70% speed...Playin most games I get 45-50C tops only the most demanding top at 55C (I will test reducing the pump speed since its at max 5 but I doubt much diff will be seen)
So I did tests again this time on my TV 1920x1080 1080p 60hz (I was using a 1920x1200 Monitor) and my overall score on Heaven increased by 5fps and about 145 score total 1763 max fps70 at Core +78 Mem +150
...however on the second try since I just wanted to give it a go again.... I did Core +91 again and it completed Heaven Benchmark with +150 Memory OC (I think i can increase Mem ill try that later) ....that was weird... Is it the number of pixels that allowed the GPU to not crash Heaven?