Hi
I reflashed my N900 some time ago and now it's gotten quite unresponsive
1. it tkes several seconds to make n900 launch an app from desktop shortcut
2. a while ago it took several seconds to make microb scroll the page after
3. the n900 is laggy even with 1150 mhz
4. everythings ok after reboot, but to make it all work alright I need to reboot everyday - and it aint handy
5. I"ve got 20MB free on rootfs with some stuff moved to opt such as microb
How can I improve the performance permanently? I'd like to avoid reflash

Don't move stuff to opt.
Export & clear your messages.
Don't install too much crap.

how long do you keep your phone turned on before this problem happens? might have a solution for you.

You've got something going on that shouldn't be. Find out what's killing you (memory, rouge process, etc), and then figure out why it's doing it. look at the process list, via top or ps, and see what's eatting lots of memory or processing speed.

Good odds you installed a bunch of crap and it's running something in the background, or something has a memory leak. My N900 is up weeks at a time (uptime is 15 days right now), and I have several things loaded (including K49 & CSSU). Still not sure, check out this post.

@don_falcone: which of stuff can be moved to opt? ovi maps
Mostly most cpu eats hildon-desktop or Xorg....

I've got dynamic cpu scaling patch and batterypatch... maybe it's issue with that

EDIT: I removed the dynamic cpu scaling and still the same

I wouldn't believe it . You can install speedpatch on top of these too and throw you n900 through the window afterward.

If you have those patches installed, I´d opt for a reflash, a clean install of the standard apps you need and a lifetime boycot on all things Karam calls "patches".

If you want to speed up things, install KP49, CSSU and QCPUFreq (ad hoc and non persistent overclocking). If you want even more after that, you´re probably better off using the combination google/rootsh/leafpad and fiddle with settings yourself.

Personally, the need to OC only comes when playing a game or with heavy use of multitasking. I found the standard mediaplayer a bit heavy on resources as well, so when I watch.movies on the phone I use the command line version of Mplayer. Usually there is no need to OC even though the standard player has hardware acceleration support and mplayer doesn´t. Long story short: find out what your needs are and experiment with what´s available in the repo´s and what works best. If nothing else works, OC as a last resort.

To reiterate what's already been said: Anything with the word "patch" after it is pretty much crap and should be avoided at all costs. Dynamic cpu scaling patch? The N900 already has that natively, without the need for a patch. If the "patch" is tweaking values, better to use a program like swapolube that at least can save/reset your default settings.

I would also recommend a clean reflash and reinstall. The built-in backup program can save and restore by category, so you can backup just contacts and calendar, then reflash and restore just those. That's the safest route.

And what's the best way to save battery? So that it lasts longer

1. As already advised , reflash to make sure there are no remnants from some "magic" on your n900.

2. Install KP49 (latest from KP thread, should be stable with SR in range 250-600 ) and use default profile if you don't want to OC. It has SR enabled for both vdd1 and vdd2. You can OC too, but have in mind that SR above 600 is still not stable on all devices (soon will be, hopefully)

3. Make sure to not install any software which polls HW every now and then.

4. use powertop, to check what wakes-up your MPU.