It's all gray.

If your screen dies, you could probably get warranty service regardless; I doubt Nokia service would turn you down.

If your phone dies outright with a CPU failure, you could be in trouble. Even if you reflash non-OC and it dies after (say, in a year), in theory they could legitimately argue that you contributed to its premature failure.

I'd say - don't do it unless you're willing to risk it all.

I'm personally running at 500 / 750 / 1000 with a custom voltage map, and I'm also hard on the device.. constantly compiling, capturing video, flash browsing, and backing up with tar/bzip2. I routinely drain the battery within 6 hours while driving the CPU up to 45C.

I recognize that my phone could pop at any moment, but that's a risk I'm willing to take, because for me, it's just the perfect device at this speed. The coolest piece of technology I've ever owned, by far. If it dies, I'll buy another.

The only thing I'm missing now is a discrete wearable display.