Here's my SR-enabled profile, which gets me noticeable lags during video playback. As an alternative I currently use non-overclocked non-modified ulv profile, lags very rarely. Same video, of course.

I must say I find it strange that you get lags with 720p libs installed (another post - are they still installed?), kernel power and if you use the dsp profile provided (sr enabled, slight overclock), yet not so much with a non-overclocked ulv profile.

Does it lag right after a reboot? This is likely o/t for kp.

Do you have swap on SD? That might help, also can you post output of iotop(in the repos) and top, is there anything to be found?

I get lags only when I have SR enabled. I have none when I have SR disabled. Both with and without overclock.

I don't see a reason to use dsp profile, because ulv's performance is fine.

I currently don't overclock my device. I will look into it later, once I've finally decided whether there is a way to make SR work properly on my device or not.

Again, I have no performance problems when SR is off. I do have performance problems when SR is on. No matter rebooted or not, when SR is on I have noticeable lags during video playback.

As far as I understand, SR main feature is to provide better battery life without decreasing performance. Well, that doesn't work for me.

Also, I have Swappolube installed with proposed options stored, don't know if it matters.

SR does the undervolting and extra undervolting can cause performance hits. Did you use SR and undervolting together?

Yes. But I stopped as soon as I realised it, that's why I asked for a link to clean default profile in this thread.

My SR profile is here, there is no undervolting there - it is just plain default kp profile with SR enabled.

As far as I noticed, xlv profile undervolts lower than SR working on my device, but it doesn't bring any performance hits.

Just reinstall kernel-power-settings to get the all the default profiles including the one named 'default'.

You are talking about 'default' profile and that you messed it up.

Just to be sure (as it was not mentioned):
You are aware that there are two occurences of default (and all other profiles)?
One at /usr/share/kernel-power-settings/
and once more at /home/user/.kernel/

Possibly you messed up the one in /home by saving but 'restored' the one in /usr? The one in /home have higher priority (are in front of the search path).
Please check also the contents of /etc/default/kernel-power (the profile loaded at boot).

First of all, thanks everybody for trying to help.

Now, back to the topic. I don't have a profile named default in /home/user/.kernel/. I do have a profile named default in /usr/share/kernel-power-settings/ and it is not messed.

I thought I messed something because didn't realise at first that kernel-config was showing voltages with SR applied AND that SR is enabled in default profile... So when I saw undervolted and SR-enabled output of kernel-config right after loading default profile I thought omg wtf... However, I didn't really mess anything.

/etc/default/kernel-power matches ulv profile, because I set it so.

SR AND undervolting were used together in custom profile I deleted, just in case.

I've tried again and again and I still get lags when using default profile and no lags using ulv profile, both non-overclocked non-modified standard profiles from kernel-power-settings.

I'm out of ideas, especially regarding the fact I seem to be the first with this problem, and kinda not at all an experienced maemo user.

I guess that FlashInTheNight86 has a h/w peculiarity here. It is well known that various editions of the n900 behaved differently to SR enabled before FMG produced the current mostly stable implementation. However, his device likely is faulty but happily ulv seems to work.

As I too lack /home/user/.kernel I assume it is made for user modded profiles and not at installation.