msi afterburner is better?
In my opinion, yes.
When they say "increase the core" what do they mean?
So the first slider is the Core Voltage. You probably won't be able to change that. It's ok.
The second slider is the Core Clock. It is linked with the third slider, the Shader Clock. When you move one, the other also moves.
The third slider is the Memory Clock.
The fourth slider is the Fan Speed. In MSI Afterburner Settings, under the Fan tab, check the "Enable user defined software automatic fan control" box. Then click OK, and check that the "Auto" button is on as well as the User Define one. You can also tweek the settings to your preferences. Then click "Apply". It should look just like the picture does.
And now, for the overclocking part. First, you must increase the Core Clock/Shader Clock by about 20MHz and click on "Apply". Then run MSI Kombustor (click on the "K" on the left side of the program window, just under the logo) for about 10 minutes. You must check for artifacts and incorrect picture rendition.
These here are all examples of what artifacts look like :
http://goo.gl/cxc3O
http://goo.gl/kXnqs
http://goo.gl/2gCea
http://goo.gl/NLIOm
http://goo.gl/XqBoq
If you see anything like that during the testing, then lower the Core Clock/Shader Clock by 10MHz and retest for 10 minutes. If it passes the test, then up the Core Clock by 5MHz and test again. Do that until you've reached the highest stable Core Clock your card can reach. Then run Kombustor for at least 2 hours and check occasionally for artifacts. If none appear, then I'd recommend running 3DMark 11 for at least 3 passes at the highest settings possible. If you don't see any artifacts, your temps are not too high and nothing crashes, then we can move on to overclocking the Memory.
It's the same method used for the Core Clock, however, I'd go by increments of 50MHz, then if it crashes, go back 25MHz and try again until you've reached a stable overclock.
With memory overclocking, you should expect complete crashes and computer reboots. It's normal. I don't know why the crashes are more severe when you overclock your VRAM than when you try to overclock the Core, but that's my personal experience.
I hope that helped,
al360ex
Edit : I almost forgot, sometimes on websites they'll see they were able to reach 5000MHz on the memory for example. Since it's GDDR5 memory, you have to divide that by 2 in Afterburner. So the software will show you a memory at 2500MHz.