Programs we will need are:
First I want you to open MSI AB, to settings then in the first general tab check both "unlock voltage control" and "unlock voltage monitoring", then it will ask you to restart MSI AB after it restarts I want you to click reset in the bottom right next to settings. Now from here we have two options regarding voltage, we can just take the voltage up to an appropriate level all at once or you can increase voltage as you increase the core clock in increments. It doesn't make a big difference because you can still always work your way down on the voltage and clocks if you feel the need to, and this way saves lots of time. If you'd like to be really conservative
about your voltages then do not proceed further,
just let me know and I'll walk you through the way that will use as little volts as possible for a desired clock speed, but I do not think that's necessary because you have an excellent cooler on that card and 1.1v is already plenty safe in itself. So let's just go ahead and set the voltage to 1.1v and set the core clock to a conservative 840Mhz. Leave the memory clock at it's stock frequency because we want to just deal with one possible variable for instability at a time, and there is much more to gain from the core so that's what we'll do first. So with your card at 840Mhz core / stock memory and 1.1v let's open up Unigine Heaven and run it with all settings at their highest (except for the "stereo 3D" option which should be left at disabled), watch while that runs for about 10-15 minutes looking out for rays of colored lights as a sign of instability. If you pass that (which you should) then up the core clock 10Mhz and repeat, running Unigine Heaven while watching for signs of instability for about 10-15 minutes after each incremental increase. You'll want to watch your temps during all this (the graph of MSI AB will keep track of them for you) and stop increasing clocks and lower the voltage a bit if you hit much more than 80C (85C is the most I would call acceptable) but you shouldn't have a problem there because of the cooler on that card. If you do have a temperature problem then stop here
and get back to me so we can set up a custom fan profile before going any further.
Once you have gotten to a point where you believe you've found some instability (most likely rays of colored lights but could also be other types of artifacts or even the driver crashing) then you'll want to lower the core clock 10Mhz back down to your last known stable speed. From here we'll do a little more rigorous and time consuming stress testing, first open up OCCT and run it's OCCT GPU test making sure that error checking is on. Let that run for about 10 minutes while watching it to keep an eye on your temperatures, if you get an error (it counts them in the top left) or your temps go above say 87-88C (this is much more stressful than any other program you'll use so a little higher than 85C here is okay, but not much higher) then immediately abort and lower clocks 10Mhz if you get an error. If temperatures become a problem then abort testing
and talk to me about making a custom fan profile.
If you can pass that then the hard part is over, now you just need to do some more long form but less rigorous testing. So you'll want to run Unigine Heaven for about 30-45min checking for signs of instability occasionally. Then run a few runs of 3DMark11, ideally if you have the paid version then just loop some test back to back, I've heard that GPU test 4 is good, but the free version is okay too. Then after that you should have a pretty darn stable OC so just begin using it as normal. When you begin playing your games though just be watchful for any artifacts (mis-colored pixels, or other ways that the game doesn't look like you expect it to) for the first couple of days of use.
That should basically be it for the core OC, if you really want to also OC your memory, which I don't ever bother with as the gains it brings are much smaller than core, then make sure your core clock is perfectly stable over multiple days of using the cards how you would normally with plenty of gaming thrown at it and then ask me to explain how to OC your memory. It's basically the same as OCing the core but a little more tedious and time consuming than the core OC, because the memory can be at a point that it appears stable but it will actually be decreasing performance. And like I said it's all for a much smaller performance gain than the core gives, I really don't bother with it myself and don't think it's worth the time for average gamers, just benchmarkers really.
Post back here if you need further help, I tried to be pretty thorough but there could be mistakes or omissions so post back if you have a question. Once you get you're OC all squared away I would appreciate it if you would consider folding on your machine as much as you are able to, we can talk more about that after your OC is done but there are links for more information in my signature.