been running at 800mhz + since over clocking became available. no problems here whatso ever.

Don't think there are any risk for frying the cpu.. but the battery could get hurt. Lucky it is so easy to change.

Overclocking is perfectly safe if you stay within 20-30% of stock speeds and you undervolt the CPU. This has always been the case with desktop CPUs with OEM heatsinks and fans for as long as I can remember.

I am absolutely certain that those running their N900 to 1+Ghz will brick it fairly soon, but I am also absolutely certain that it's perfectly safe at 750-805Mhz.

Care to put some numbers on the "fairly soon"?

Consider that it is 5 months since overclocking became widespread.

Been running @ 1150mhz since the start, would buy another n900 if it ever died, but it only runs at that speed when required otherwise it scales the CPU down.

oc'd to 1ghz soon as titans kernel was considered stable, aint undone it since, no major flaws, not even any minor ones i would blame on the oc'ing. the processer in one of these wouldn't be the first thing to die, rough guess i'd say five years since theres no heatsink? yes no? if it burns out in 18 months i'm not that bothered cos i'll have a new contract and new phone by then.

if you're scared dont do it, you'll just keep yourself awake at night with worry.

I was at 850 max (using ideal settings) for over two months. Never seen any lock-up. For a few days I have pushed to 1 GHz. Nice it's very nice and the difference from 850 is noticeable. I will see how far it goes with this setting. As Tiboric said it scales down to 500 Mhz when it is idle, which for me this is major portion of the day.

See, it all comes down to how lucky you are. I am much more familiar with fab processes for desktop and laptop CPUs, but I'm willing to bet money they are identical for mobile CPUs.

When AMD designs the next generation CPU, they really do not differentiate between a 2Ghz or 3Ghz part, a 1, 2, 3 or 4 core part or the amount of cache. They build the exact same CPU in exactly the same way.

Before final packaging, they test the CPU and see how fast it can go, what parts are defective, etc. Based on that they set the speed, disable some of the cores and some of the cache. This is a bit simplistic, but it generally holds true.

So if you got lucky and your N900 has a high spec CPU, then it can run forever at 1+Ghz. But you can't determine that until you fry it. However even low spec CPUs are pretty much guaranteed to run at a modest speed bump since Nokia has to leave a margin of error.

In all honesty I'd be MUCH more worried about breaking off the damn USB connector and ruining my N900 that way since it's a KNOWN design flaw.

BTW, I've been running my N900 @750Mhz and I'm sure it will survive the useful lifetime of the device. In other words everything else on it will break before the CPU fries.

The only issue I ever had was when I OC'd to 1.15Ghz it just rebooted, since then I've kept it at 900Mhz, and all is good

So the short version is that your claim:
was meaningless?