Hello,
I tried overclocking my n900 using titans kernel and just tried ideal. I then tried to play a video and "minimize" it. It rebooted. I thought it was because of the low voltage. So I put "lv" profile with limits 250 950. The phone rebooted after a while while playing a video in the default player... Does this mean that my phone cant be overcloked to 900+ like everyone else's(well, most of their's)? Is there anything i should try?
+ I've put a poll just to know how many people keep their phone overclocked.

Tried overclocking the default kernel?

Just use:
sudo gainroot
kernel-config limits 500 850

Don't change to the ideal or lv kernel. See how that goes.

You can always try just stock voltages. eg. stock instead of lv.
But yes, there are a number of people who are quite unlucky.

Mine has been overclocked 24/7 @ 1GHz using ULV profile for past month or so. Zero issues so far.

I think I remember some people saying that 950MHz causes problems for them, even when higher freqs work fine for them (when they add 950 to avoided freqs, or increase volts for it).

Mine doesn't work at 950 either, but it's stable at ideal profile, and seems to also work with starving profile @900 (have been trying that a few days now, no strange stuff so far). Haven't tried disabling 950 and going over that, 900 is quite enough for me.

The poll is kinda unclear; I leave my N900 set to 1GHz maximum clock mostly, but that's only the maximum; it spends most of its time on a lower clock or completely idle. Do people really manually set the maximum frequency up and down depending on "heavy multitasking", or are you guys just picking option #3 to represent the behavior of the ondemand governor?

Anyway, IMO the thing to do when overclocking is not necessarily to try a bunch of preset voltage profiles, but to build out from the best known-good profile (and if none of the lv, ulv, xxxxxlv, etc. work, the standard one is known good for 600MHz and lower, right?), scaling one clock step at a time, and finding the voltage required for stability. I'd just kick the speed up at the 600MHz stock voltage, and find where it loses stability, or the max, then kick voltage up/down for stability; from that point, you can estimate from the existing profiles how much to tweak the voltage for nearby speeds.

Once you've got stability for every clock you care about, you can go back for efficiency, stepping through all the lower clocks: lock a frequency, decrease the voltage till it crashes, add 2 for a margin of stability, and repeat. It's much less frustrating going down (and getting one crash when you get there) than going up (and getting repeated crashes until you get there).

Thanks for replies. The lv profile works for limits 250 850. Dont want to OC on stock as it'll consume more battery.

EDIT: lv stable at limits 250 900