So, not wanting to be completely useless figure here at the forums I decided to write something about overclocking. More specific, about graphics cards.
They are easier subject to approach than overclocking your CPU, there is simply too many different kinds of processors out there to quickly cover that area.
If the people wants I might give that a shot too, atleast the basics of it.

Anyways, here are two links to 3DMark 11 results

Result 1

Result 2

The first thing you want to notice is that I started the second test less than 30 seconds after the first one stopped.
How did I manage to get 400 more points without changing any hardware? Well, by overclocking my graphics card ofcourse. More specific, using a program called MSI Afterburner

The program allows you to change several parameters from your card directly at desktop and apply them without rebooting or any other pesky stuff like that.
And even if it's called MSI Afterburner it's not limited to MSI's cards only. Mines Asus and it works fine.
It works with both ATI and Nvidia cards and it doesn't have to be brand spanking new to work either.



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And this is the screen that welcomes you when you've installed and started it up the first time. Up you can see your card make and installed driver version, the part we are now focusing is Core Clock.
This is your GPU or graphics processor speed. Mine's running at stock in this picture, 775 MHz. The clockspeeds are a lot less than on your CPU would have. And increases 100MHz or so would have a lot greater impact on gaming than increasing your new quadcores speed by just 100Mhz.

Now, there is no magical number that is the maximum your GPU can achieve. This is all done by trial and error and if you want to achieve speedboost to games w/e you are going to have to put some time into this.
Ofcourse the easy way is to try and search with google what other people have managed to get from similar card.

Before you touch anything you'll need a program to test the stability of your card. MSI Kombustor works fine, it's based on Furmark and it kinda integrates into Afterburner.
Once installed hitting that K on the left upper side of afterburners main screen starts Kombustor immediately.
You can exit Kombustor \ Furmark by hitting ESC.

Now, let's start raising those clockspeeds. First things first, just ONE at the time. If you move them all at once and it isn't stable... well.. You'll do a lot more work in finding out wich one is giving you hard time.
Increase the Core Clock slider by small increments, say 10 or 15 MHz, at a time. Don't be alarmed if the Shader Clock slider also moves. On some cards, like my GTX 460, you can't unlock them from each other and where one goes the other will follow.
You can also directly type in the number you wish to the screen on the right side of the sliderbar.

Once you have wanted MHz selected hit Apply from the bottom and start Kombustor \ other benchmark software.
If it reboots the computer and \ or resets your video driver it's gone too far and you need to back out a bit. Or rise the voltage, but we won't be going into that as it also increases the chance of you damaging your card. If you can't see the monitoring screen that tells you your GPU temps and such you should enable it now from Afterburner.
Settings

If the program starts and you see a hairy MSI-logo spinning around all is good so far. Let it wobble there for a while.
Keep an eye on the GPU temperature, if it raises too much it ain't worth it. Maximum safe depends on the chip greatly and info for particular ones can be found on the interwebs. I keep a rule of thumb that I won't let it over 80 Celsius.
For the GPU in my card Nvidia says 104 degrees celsius is the temperature where it starts to automatically throttle down to avoid burning but that's a lot. For comparison to those who are unfamiliar with metric units water starts to boil at 100 degrees celsius.

And that chip isn't the only thing that get's heated up there. I blew a power capacitor on my previous card. It was propably faulty but it could as well as been a result of bad airflow in case, too high temperatures on the capacitors themselves.
In another words, good case airflow for cooling is important. It should be important even without any overclocking.

One thing you should keep an eye out for is also the spinning MSI logo on Kombustor, specially on overclocking the memorychips. If there's any strange artefacts, strange dots appearing, colors showing wrong or noticeable FPS drop it isn't stable. Back down on the MHz.

If it runs OK for 10 minutes or so stop Kombustor and increase clock speed a step or two more. Rinse and repeat.
When you think you've hit the maximum stable overclock with these methods let the test program you are using run for extended perioid of time. I personally run it for an hour or so to see if it acts funny. BSOD, crash, freezing and stuff like that.
Even after that I may crash while you are playing a game.

When you've got your results you can save them to profile from the mainscreen and click that ball left to text 'Apply overclocking at system startup'
You should also go to Settings -> General and select Start with windows. Without that it won't apply OC on system startup, atleast for me it doesn't.

That long wall of text being said, there is NO such thing as free power. Not even with overclocking. Depending on how much you push your card it will generate more heat and draw more power.

And there is always a risk of damaging your equipment when running them on higher speeds than ment. Use at your own risk, warranty is usually void if you overclock your stuff.

Edit; For comparison did some benchmarking with the card I have now, Asus directCU HD6870 radeon
With stock core clock of 915MHz 4091 3Dmarks in 3Dmark11
Result

And with 950MHz clock 4195 3Dmarks.
Result

Memory clocks not touched and voltage not increased in these, 950MHz is as fast as this card goes with stock voltage. MSI Afterburner doesn't allow me to increase it.
I could use Asus GamerOSD to increase volts and put more clock to it but that program gives me diarrhea.
Increase of around 100 points might not seem a lot but it still might be enough to push your FPS to playable from unplayable or allow you to put some cool effects on.

And if you are running a non-overclocked 6870 with stock clock of 900MHz difference should be noticeable.
But then again, your card might not overclock or it might go even further with stock voltages. You never know when it comes to these things.
Trial and error.

Very nice. It's great to see these well researched, well thought-out jewels amidst the sea of DURR WHICH HEADSET SHOULD I BUY HURR? threads.

+Karma for you, sir.

jermizzey wrote:

Honestly sick of those... And yeah this is pretty awesome I appreciate it. I think I'll leave my 5770 where it is for now cause I can run everything how I want anyways =]

Karma

oHai_iPrestoNi wrote:

And here's something I forgot to put to the original post. If it runs fine, don't mess with it :>
Unless you are like me and for some strange reason that has no proper logic behind it you want to.

Myssi wrote:

I am like you. I overclock for no reason. lol.

Thanks for this man!
Really helpful!

Bump + karma. Been looking for this for a while.

Updated 03/28/2011, added few test results.

nice little guide, but nothing an avid pc gamer wouldnt know about.
honestly its not that hard to overclock anything, just need to know the right numbers, which google can help you out.

imo, overclocking your gpu is useless and not needed.
most of the cards are fast enough to do anything as it is. overclocking it an extra 200-400mhz for a small increase isnt worth the time and possibly a blown card (lawl)

Blak0ut wrote:

This comes from the assumption that people can actually use google or search functions on the internets.
And well, yeah. 4 new threads on the same particular subject here per day so...
And to avid pc gamers this should be easy as pie and the guide is in no means ment to someone who is already experienced fiddling around with your pc.

You'd be suprised but everyone who owns a pc doesn't grasp the idea what overclocking is or does and some of those might still be interested in seeing can they pull some more power out of their systems for "free".

And on the uselessness of overclocking your gpu I have a different opinion but meh, that's life.
The GTX460 had noticeable increase in performance on BFBC2 for example with simply increasing the clock from 775MHz to 915MHz.
These 'only few hundred' applied to CPU would have propably no effect but we aren't talking about CPUs here.
The choice is it or is it not worth it is up to each invidual themselves.

well when someone buys an msi gpu and it comes with afterburner, i would hope they do some reading to see what it does.

most of the time overclocking isnt needed. you may see a performance increase, but 90% of the time its a roughly a 5 fps, depending on the game.
also you need to factor in what resolution/settings the persons is running.

overclocking is good, but meh..

Blak0ut wrote:

Yup, the resolution you play with has a big meaning in all of this. Not going to disagree with that one.
With grandmas old 17" panel you are more like depending on the cpu anyways and not the gpu because of the low resolution and if I'd have money for proper screen with a resolution like 2560x1600 instead of this Full-HD the impact would have been far lesser.

Myssi wrote:

QFT.

along with that 590.

Blak0ut wrote:

You guys are noobs, I'm sitting here laughing at you on my Quad-socket Opteron, 48-core computer with 128Gb of RAM and Crossfire 6990's.

jermizzey wrote:

Does it run Crysis?

eww opteron.

is the GPU temp in the top right corner of kombustor? cos thats what it says but it says its 0? :/

Mattatron17 wrote:

the temp is the graph below.

the graph below what? where it says GPU temp cos im pretty sure there aint one?

Clicky T to toggle the graph. Or I to toggle everything.

thanks but pressing T doesnt do anything :L

Mattatron17 wrote:

What card are you running?

[model/manufacturer]