If you buy an enthusiast board, it will be equipped with an OC profile feature in the BIOS. This might be used for example as follows:
1. 24/7 OC - with SpeedStep, HT, Turbo features enabled.....almost all BIOS features on Auto (Vcore = 1.1125 / DRAM = 1.5625) This is your everyday OC and it still allows the CPU to throttle down when demand isn't there. On the box I am typing from, Intel 920 w/ Asus Rampage II Extreme and Megahalems cooler, the CPU OC here is 3.8 GHz and CPU temps under Prime 95 are in the mid to hi 50's.
2. Gaming OC - This is tweaked a bit higher and more BIOS features are manually set . OC here is 4.0 Ghz , w/ temps in the hi 60's low 70s under P95. Used only in the most demanding games.
3. Limits OC - This profile is the highest stable OC that was achieved and has many BIOS settings tweaked. OC here is 4.2 Ghz and temps top out at 71 - 74 under P95. Used only for "educational / experimental" purposes
4. Stock setting - self explanatory
(95% of the time, Profile 1 is used ... with stress tests only in the 50's CPU life is not a concern.
I don't usually have the builds here very long before user picks them up....so usually only have about 48 hours. On "in house" builds, I set a side the weekend to do the build and OC .... final tweaking the following weekend. This can't eb done however if ya use AS5 as you need 200 hours and weeks of start up / shut downs before he TIM cures. See the "Important Reminder" at bottom of page here:
http://www.arcticsilver.com/as5.htm
As for the GPU, faster clocks simply mean more fps. The factory OC'd 560's (900 MHz) for example are about 10% faster then their reference counterparts .... pushed to 1000 MHz, they approach 20% boost.
Now for the tips ..... while your components are in a brown truck traveling across country, visit all the manufacturer's web sites and download product manuals, installation instructions, firmware updates, drivers whatever. print out the manuals and read them .... several times. Most of the "how to" build questions ya will see posted here can be found right in the manual. Visit the local hardware store and make sure ya have all the necessary tools and supplies including plastic zip ties, cable clips, etc
http://www.frozencpu.com/products/3795/tiw-10/7_Red_Tie...
http://www.frozencpu.com/products/8044/tiw-109/ModSmart...
The little yellow hyperdermic looking thingie in the lower left of the picture here:
http://www.frozencpu.com/products/3837/too-08/Ultra_130...
has 3 prongs that stick out when ya press the plunger and retract upon release....I call it a screw grabber and I find it's the most "handy" of tools.