The best graphics card overclocking utility out there :
http://event.msi.com/vga/afterburner/download.htmWorks fine for nVidia and AMD video cards...
You are correct, only need to tweak gpu voltage and the gpu clock... when you increase the base clock on these newer nVidia cards you are also boosting the "boost clock" on them by the same amount unless the card is under heavy load, then the "Boost Clock" goes even higher than the standard boost amount... they are "linked" together except under heavy load conditions ( base clock and boost clock ) , see review below for more details on this:
If you buy the Gigabyte GTX 670 ( awesome card btw ! ) , here is a review on it:
http://www.bit-tech.net/hardware/graphi ... b-review/1Let's recap. The GTX 670 2GB is essentially the same 28nm Kepler GK104 GPU featured in the GTX 680 2GB, but with one of its SMCs removed, thus leaving it with a total of 1,344 stream processors and 112 texture units. It also sports seven of Nvidia's Polymorph engines for tesselation duties, and four rasterisers.
At stock frequencies, the card has a 915MHz core clock speed, with a boost speed of 980MHz (although the card will boost past this under heavy load). Gigabyte, however, has applied a modest 7 per cent overclock, taking the core clock speed to 980MHz for a boost clock of 1,058MHz, though the card actually reached 1,162MHz in our testing.
Skyrim performance:
Skyrim tends to favour Nvidia hardware, so it's unsurprising to see GeForce cards do better than their Radeon counterparts. Nonetheless, the Gigabyte GTX 670 2GB clearly outperforms the HD 7970 3GB in every test, and either beats or equals the costlier GHz Edition in each test too, which is an excellent result.
How they overclocked it:
http://www.bit-tech.net/hardware/graphi ... b-review/9Gigabyte GeForce GTX 670 2GB X Turbo - Overclocking
As Gigabyte's overclock is a fairly modest one, we were hoping to be able to squeeze some extra juice and higher frame rates from its card, especially as it houses an extra power phase. We fired up EVGA's Precision tool for the job, and once we'd settled on the highest stable overclock, repeated the Unigine benchmark and the Battlefield 3 2,560 x 1,600 test to see the impact.
We ramped up the voltage the maximum available, which was 1175mV, and also increased the available power to the maximum of 112 per cent. With these settings, we were able to add an extra 100MHz to the core clock, taking it to 1,080MHz. This represents roughly a 10 per cent overclock, or an 18 per cent one over stock frequencies, which is not too shabby. It's also 40MHz higher than we were able to overclock the stock GTX 670 2GB to. The claimed boost clock at this setting is 1,159MHz, but we saw it boost to 1,254MHz in use.
As for the memory, we were able to clock it up by a whopping 350MHz (1.4GHz effective) before the card begun to become unstable. This gave us a memory frequency of 1.85GHz (7.4GHz effective), a 23 per cent increase, far higher than the 1.7Ghz (6.8GHz effective) we managed with our stock sample. At these frequencies, our power draw test took our peak system power consumption up to 284W.
Okay, so they pushed the gpu voltage to the max allowed by EVGA Precision overclocking tool ( works fine but I hate the interface, much prefer MSi Afterburner which offers more fan options ( completely adjustable fan speed curve ) and is widely regarded as the best gpu tweaking tool out there, just saying...
Anyone can push a component to its limits and beyond when the component is brand new and they only test it for a week or two then write the review. I warn you not to push the max voltage possible to your gpu because you will eventually fry the card. For example, My 1 year old EVGA GTX 560 Ti "FPB" card fried on me from running 5 to 10% increase in cpu voltage ( only during gaming ), and pushing the gpu speed from stock 850 Mhz to 950 Mhz ( typically, and again, only during gaming sessions , rest of the time I ran it stock voltage and speed ). I monitored the gpu temp with Afterburner and the card never exceeded 60C during full load heavy gaming... which is supposed to be a low "safe" temp for this card ( nVidia says 105C is the "max" gpu temp for this card ) and I never got anywhere near that temp, ever on my card.. yet it still died on me even though I thought I was giving it a very mild gpu voltage increase and frequency increase ( compared to what some people and reviewers out there do with their cards

).
So to make a long story short, if you want your card to last you a long time ( more than a year for example ) then you will not increase the gpu voltage at all, and only increase the gpu and memory speeds when gaming... my advice...If you overclock the gpu by 5% and memory by 20% then you will have GTX 680 level performance without having to bump gpu voltage or risk frying the card over time...
Once you get the card and begin testing it then we can give you further advice, but the above should give you a good baseline to start from...hope you get your new card soon! cheers!