When is it worth it?

When you need or think you need more performance. Sure, my i7 920 was fast at stock speeds, but not fast enough. So I have it modestly overclocked to 3.6GHz without HT.

Overclocking does not cut the lifetime of a product significantly. Sure, we might be talking about 2-3 years here... but what's that in a 10 year CPU lifetime? Before overclocking would substantially damage your parts, you probably would have upgraded to bigger and better components.

Overclocking your video card is probably the easiest. There are software out there that will literally do it for you, but for now check out drivers at ATI's site and download their Catalyst Control Center (CCC) which should be able to overclock your GPU through their overdrive stuff. If not, download ATItool (which comes included with an artifact scanning/3d benchmarkish tool) or Rivatuner.

I tried OCing my GPU... it went successful, I thought. Obviously my computer thought other wise.. I decided since it was my first time I'd let ATI Overdrive from CCC do it's automatic thing.

Temps went from 56C to 80-85C, at 99% GPU activity, and "idle" (I guess, 0% GPU activity) in the 60-70s. Core speed went to 840 MHz while the memory clock speed went to 850-890, can't remember... from both being 700. However, the "current values" thing said the GPU clock was still at 110 MHz and mem clock at 700 MHz, so I realized I needed to tick "Enable ATI Overdrive"... which made my screen flash, and crash. I booted again and unticked it if it hadn't been automatically, and messed around with them myself - trying lower clock speeds with the same proportions, etc. and decided to test it in game.

Got LOW fps - talking around 50% or so of what I normally get. Right after a restart and smart-close, too, so it wasn't anything out of the ordinary. I decided to untick the enable ATI Overdrive button, figuring that'd reset it all to stock speeds... but apparently not, because I'm still getting really low FPS.

I tried playing War Rock - an EXTREMELY low-end game, and my FPS with 1440x900 reso and high graphics, which I could normally run, was anywhere from 17-30 FPS. That's really, really low for this game. It isn't playable at 30 FPS by anyone, usually a decent FPS is considered 120-142ish (it caps at 142).

So I'm at a loss for what happened. "110MHz" seems extremely low for the GPU clock so maybe that's it, but I've been noticing those #s don't change. I'd like to laugh at myself and say, "LOL, none of this worked! Nothing was ever OC'd or changed at all," but I'm still getting bad performance (in general performance, not just fps), so something changed and is still changed - after another reboot.

Plus, my temps are a wee bit higher at 0% GPU activity as well.

Basically, I'm just confused as to what happened and how to fix it. I highly doubt I'll be OCing my CPU or anything on this computer, I have nothing to fall back on - and why fix something that isn't broken. I'll probably try my hand at it again when I build my new rig... maybe... but until then, I really don't wanna be stuck incapable of gaming.

"Bleh". I doubt many people are on this late and early (hmm, 9AM GMT, so maybe some Europeans are on - thought it was earlier...), so I'm going to Google any keywords I can think of on how to fix this, and I'll update if I've figured it out.

The ATI overclocking tool, on the "auto" overclock setting, is a complete joke. You will never get a sucessful overclock using that worthless piece of crap for a program.

You start by slowly raising the core speed manually, a little at a time, like 10mhz, and testing by playing a game or running a benchmarking program like 3D mark 06 a few times through. If all goes well, you up it a little more. Moderation and testing is what overclocking is all about. Small increments with lots of testing in between.
You should be able to get your 4600 to around 2.6 ghz pretty easy just by raising the FSB to around 215. Depending on how touchy your memory is, you may need to lower your memory speed a little. Just remember that when you raise the buss speed, you are also increasing the speed of the memory. Most memory is pretty sesnsitive and will not stand much overclocking, so you have to keep it running close to it's rated speed as you raise the buss speed.
Download CPUID so you can see the results of your overclock when you boot.
CPU speed, memory speed, buss speed, etc.

I did the overclock tool on the ATI Catalyst Control Center with 2 HD 4890's w/crossfire and when I used their clock speeds it froze 3DMark06 while I was checking it so I lowered it on my own and it worked great. You need to make sure you have your fans are running at higher than stock levels my fans will run at 20% if I dont manually go in and change the speed. My numbers are with ATI Overdrive enabled: GPU Clock 850 Mhz, Mem Clock 990 Mhz @ idle my fans are at 63% and my temps are 44c/42c. Now thats on my HD 4890 I dont know which card you have so your numbers may not even come close to what I have but like jitpublisher said dont rely on ATI overclocking tool it does not do a very good job