[Nexus 7 Q&A, Help & Troubleshooting] bftb0:
I don't yet - I might later. My N7 is still less than a month old.

The device manufacturers (e.g. Asus in this case) have motivations to "not leave anything on the table" when it comes to performance. So, you have to ask yourself - why would they purposely configure things to go slowly?

After all, they need to compete with other handset/tablet manufacturers, who are each in turn free to go out and buy the exact same Tegra SoC (processor) from Nvidia.

At the same time, they know that they will manufacture millions of units, and they want to hold down their product outgoing defect levels and in-the-field product reliability problems to an acceptable level. If they don't keep malfunctions and product infant mortality down to a fraction of a percent, they will suffer huge brand name erosion problems. And that will affect not only sales of the current product, but future products too.

That means that they have to choose a conservative set of operating points which will work for 99+ % of all customer units manufactured across all temperature, voltage, and clock speed ranges. (BTW, Note that Asus didn't write the kernel EDP & thermal protection code - Nvidia did; that suggests that all the device manufacturers take their operating envelope from Nvidia; they really don't even want to know where Nvidia got their numbers)

Some folks take this to mean that the vast majority of units sold can operate safely at higher speeds, higher temperatures, or lower voltages, given that the "as shipped" configuration will allow "weak" or "slow" units to operate correctly.

But look, it's not as if amateurs - hacking kernels in their spare time - have better informed opinions or data about what will work or won't work well across all units. Simply put, they don't know what the statistical test properties of processors coming from the foundry are - and certainly can't tell you what the results will be for an individual unit. They are usually smart folks - but operating completely in the dark in regards to those matters.

About the only thing which can be said in a general way is that as you progressively increase the clock speed, or progressively weaken the thermal regulation, or progressively decrease the cpu core voltage stepping, your chances of having a problem with any given unit (yours) increase. A "problem" might be (1) logic errors which lead to immediate system crashes or hangs, (2) logic errors (in data paths) that lead to data corruption without a crash or (3) permanent hardware failure (usually because of thermal excursions).

Is that "safe"?

Depends on your definition of "safe". If you only use the device for entertainment purposes, "safe" might mean "the hardware won't burn up in the next 2-3 years". Look over in any of the kernel threads - you'll see folks who are not too alarmed about their device freezing or spontaneously rebooting. (They don't like it, but it doesn't stop them from flashing dev kernels).

If you are using the device for work or professional purposes - for instance generating or editing work product - then "safe" might mean "my files on the device or files transiting to and from the cloud won't get corrupted", or "I don't want a spontaneous kernel crash of the device to cascade into a bricked device and unrecoverable files". For this person, the risks are quite a bit higher.

No doubt some tool will come in here and say "I've been overclocking to X Ghz for months now without a problem!" - as if that were somehow a proof of how somebody else's device will behave. It may well be completely true - but a demonstration on a single device says absolutely nothing about how someone else's device will behave. Even Nvidia can't do that.

There's a lot of pretty wild stuff going on in some of the dev kernels. The data that exists as a form of positive validation for these kernels is a handful of people saying "my device didn't crash". That's pretty far removed from the rigorous testing performed by Nvidia (98+% fault path coverage on statistically significant samples of devices over temperature, voltage, and frequency on multi-million dollar test equipment.)

good luck!

PS My phone has it's Fmax OC'ed by 40% from the factory value for more than 2 years. That's not a proof of anything really - just to point out that I'm not anti-OC'ing. Just trying to say - nobody can provide you any assurances that things will go swimmingly on your device at a given operating point. It's up to you to decide whether you should regard it as "risky".