GPU Overclocking GTX 780

[TheBeeMuzza]

Hey everyone,

I got my 780 today and I'm pretty happy with it, but what I want to know is can I make it even better without me getting any problems, I tried google searching for previous people with the same card who has overclocked it but since it's an exclusive model it's hard to find, here is my model of the 780 I have: http://www.overclockers.co.uk/showproduct.php?prodid=GX-033-IN

What I need is someone who knows what they're doing that can tell me how to improve this by overclocking, I ran the Furmark 1920x1080 15minute burn in benchmark and I got average FPS of 74 and it finished with load at 98% and at 62 degrees.

So what can I do?

 

[TheBeeMuzza]

Download EVGA Precision X - a very easy to use overclocking tool. There will be a few sliders on the main screen. Push the power limit to the max, then try raising the core clock and the memory clock sliders (the bottom two). Then test. There's a very healthy overclock on your card already, so I'm not sure how much further you'll be able to push it.

Download GPU-Z to see your clock speeds.

got this so far: http://gyazo.com/3035672ac8015f3de06d77dfd4ac422e

 

[TheBeeMuzza]

If you raise the clocks by 5 and 10 each time you'll be here all night Put, let's say, 20 on the core and 100 on the memory.

Can you post a shot of GPU-Z?

IIRC the core clock has 13MHz bins so you will need to go +13, +26, etc. to actually go to a higher speed on the core. (So stability testing on 5MHz steps is probably a waste of time).

EDIT: Also saying push the power limit to the max isn't necessarily good advice - some cards will let you push it way beyond safe levels (even if you don't hit it) while others will limit to i.e. 106-119% which is fine.

Alright, here's what I've done now: http://gyazo.com/8740c063158f22e79e816e8fc52d5096

 

[TheBeeMuzza]

Yeah usually means that speed bin isn't stable - if you want to overvolt then usually you will get one speed bin higher stable for every extra +13mV or something like that (tho still a bit of a lottery with core quality and cooling).

This is a fairly good reference http://www.altesc.net/2013/06/15/gtx-780-overclocking/ though you might need to adjust the numbers a little depending on your card and what the base speed on it is.

Was this aimed at me or the guy above?

 

[TheBeeMuzza]

You can also look for reviews e.g. http://hexus.net/tech/reviews/graph...ll-geforce-gtx-780-herculez-x3-ultra/?page=12

That's the non-DHS version, but I assume they're essentially the same. Don't go for that kind of overclock immediately, but you can see why going up in such small increments might take a while.

First part was in response to the guy I quoted, 2nd part is possibly useful information for anyone.

Alright, now how can I tell when I've went over, will there be an immediate effect when I've went too much?

 

[TheBeeMuzza]

In terms of voltage or stability?

Stability wise I usually find one speed bin too high will black screen inside 1 loop of heaven benchmark, 2 too high will result in artifacts and 3 results in random hardlocks or BSOD. Backing off one speed bin from the one that black screens heaven usually seems to result in 100% stability in anything.

Voltage wise you will (if it is too high which most cards won't let you) start hitting the power limits and the core clock will be automatically clocked down which you can see in GPU'z sensor graph.

Alright, think I'm going to leave it at this, don't want to end up getting errors or doing something wrong, since I don't fully understand! http://gyazo.com/79198d7f665db8a87989a782cebf6060

 

[TheBeeMuzza]

106% power limit will be fine don't worry about that - its just some cards like mine allow for power limits that are potentially above safe levels if you don't know what your doing.

In GPU-z sensor tab watch what the core MHz is actually at when running a stress test - it will go up in 13MHz steps - so once you find where its getting a black screen in heaven back the core down until it drops -13MHz in GPUz during testing and you should be stable in most cases.

If you then want you can increase the core voltage by +13mV and try again with the extra 13MHz and so on until you find where its unstable again.

Alright, that made it easier, thanks for your help man!

 

[TheBeeMuzza]

A little more complicated but this probably illustrates it better - say you have a card that actually boosts to 1045MHz out the box:

+0 = 1045 actual boost
+1 = 1045 actual boost
+12 = 1045 actual boost
+13 = 1058 actual boost
+15 = 1058 actual boost
+25 = 1058 actual boost
+26 = 1071 actual boost
+27 = 1071 actual boost
+39 = 1084 actual boost - (+18MHz on memory clock)
+52 = 1097 actual boost - max stable - (+36MHz on memory clock)
+65 = 1110 actual boost - black screen - (+54MHz on memory clock)
+78 = 1123 actual boost - artifacts - (+72MHz on memory clock)
+91 = 1136 actual boost - BSOD/hard freezes - (+90MHz on memory clock)

Exact numbers might need adjusting to the specific card but it will always be 13MHz steps - the non bold values are just to illustrate that the actual boost clock won't change between the 13MHz steps.

I've also added some notes on the memory clocks - I find that the stock 1500MHz (6000 effective) memory speeds start to starve the core a little once your hitting ~1070MHz boost clocks in many cases - the memory goes up in 6MHz steps but you need to add +18MHz (upto whatever your memory is stable) for every 13Mhz core bin to help balance it out - going higher on the memory clock won't hurt if its stable but thats the baseline I find to nicely feed the core.

EDIT: You might find that a memory overclock seems stable but your game/benchmark becomes stuttery - in which case back the memory clock down 6MHz until it becomes smooth again.

Awesome, I'll leave the core at +39 and leave it there for tonight I'll keep gradually adding to it to max it out