Wrong, it depends on the mainboard.
There are mainboard specifically designed to allow overclocking and bypassing safe values, and if you have one of those (they're usually more expensive and not in base configurations), then you can cause a lot of problems and defects by overclocking.
That I didn't know, on my Asrock there is nothing above 1866 Mhz. I can go below, but not above.
Also I thought, as long as you don't raise voltage no real damage could been made.
Because you can allways BIOS reset, if you overclocked too much. If you overvolted too much, then you can destroy your hardware, that I know.
Could be because of overheating or overvolting damage. First mostly can be fixed, while waiting a few moments and then turn the power on to the system.
The second if happens you can mostly buy new hardware. :/
*off topic*
For example NVIDIA couldn't be overvolted beyond 1,15 Volt, which I use on my GPU. The clocks you need adjust with try and error, most of. But if you go way too high you see it because of graphic errors.
*on topic*
On RAM it's different, because Windows will allways run, without trouble. But if you start up a game, or complex programm, it will probably crash with error message x. :/
For my RAM I can't change a thing, if I go from 10-10-10-30 down to 9-9-9-27 it crashes. Same if I go to 11-11-11-33. So nothing to do there.
If I raise the clock from 1866 up to 1886, it crashes, if I play games or convert a video. Windows runs allways fine, as I said.
Even I was going up to 1,65 Voltage on the RAM with 2000 MHz, Windows run, games are running some, but videoconverting crashes. :/
I have no problem with too hot RAM, because they got heat shields. But sometimes it's not the RAM that causes the trouble, instead it could be the mainboard itself. -.-
Why does overclocking need to be that complex? -.-' (\s/)