Sorry for writing response to my own post but it's technologically impossible to edit previous one. So here is my powertop while idle (with some applets running: sensors, backlight, power, cpufreq-utlis, nm-applet + opera and firefox in background)

Additional ondemand governor makes my cpu jump from 800 up to 2,4 ghz every 2 seconds on total idle state.
Just after system start it looks quite nice, but after some minutes amont of unnecessary wakeups grows dramatically from 40 up to 3000.

Next strange thing is acpi wakeups (why?) and extra timer interrupt. All those things clearly shows that cpu is very busy while in "top" command I've got only Xorg with 10% cpu and opera 4%. Everything else is under 1%.

---------------------------------------------------------------------
PowerTOP 1.9    (C) 2007 Intel Corporation 

Collecting data for 15 seconds 
Cn	          Avg residency
C0 (cpu running)        (13,4%)
C1		  0,0ms ( 0,0%)
C2		  0,0ms ( 0,4%)
C3		  0,9ms (86,2%)
P-states (frequencies)
  2,41 Ghz     0,0%
  2,40 Ghz     0,0%
  1200 Mhz     2,0%
   800 Mhz    98,0%
Wakeups-from-idle per second : 1190,9	interval: 15,0s
no ACPI power usage estimate available
Top causes for wakeups:
  90,7% (2086,5)      <kernel IPI> : Rescheduling interrupts 
   2,6% ( 60,3)       <interrupt> : PS/2 keyboard/mouse/touchpad 
   2,1% ( 47,6)       <interrupt> : acpi 
   1,2% ( 26,8)       <interrupt> : extra timer interrupt 
   0,6% ( 13,5)       <interrupt> : iwl4965 
   0,5% ( 11,2)         nm-applet : schedule_timeout (process_timeout) 
   0,4% ( 10,3)   gnome-settings- : schedule_timeout (process_timeout) 
   0,4% ( 10,0)   cpufreq-selecto : cpufreq_governor_dbs (delayed_work_timer_fn) 
   0,4% (  9,2)             opera : schedule_timeout (process_timeout) 
   0,3% (  8,0)   <kernel module> : usb_hcd_poll_rh_status (rh_timer_func) 
   0,1% (  1,8)    wpa_supplicant : schedule_timeout (process_timeout) 
   0,0% (  1,1)    NetworkManager : schedule_timeout (process_timeout) 
   0,0% (  1,1)        pulseaudio : schedule_timeout (process_timeout) 
   0,0% (  1,0)       <interrupt> : uhci_hcd:usb3, yenta, nvidia 
   0,0% (  1,0)    cpufreq-applet : schedule_timeout (process_timeout) 
   0,0% (  1,0)              Xorg : nv_start_rc_timer (nv_kern_rc_timer) 
   0,0% (  1,0)            dhcdbd : schedule_timeout (process_timeout) 
   0,0% (  0,9)              Xorg : do_setitimer (it_real_fn) 
   0,0% (  0,9)              Xorg : schedule_timeout (process_timeout) 
   0,0% (  0,7)    sensors-applet : schedule_timeout (process_timeout) 
   0,0% (  0,7)     <kernel core> : neigh_table_init_no_netlink (neigh_periodic_timer) 
   0,0% (  0,7)   gnome-screensav : schedule_timeout (process_timeout) 
   0,0% (  0,5)   <kernel module> : neigh_table_init_no_netlink (neigh_periodic_timer) 
   0,0% (  0,5)       <interrupt> : eth0 
   0,0% (  0,5)       <interrupt> : ahci 
   0,0% (  0,5)           iwl4965 : ieee80211_sta_work (ieee80211_sta_timer) 
   0,0% (  0,5)    NetworkManager : e1000_intr_msi (e1000_watchdog) 
   0,0% (  0,5)       gnome-panel : schedule_timeout (process_timeout) 
   0,0% (  0,4)    gnome-terminal : schedule_timeout (process_timeout) 
   0,0% (  0,4)           firefox : futex_wait (hrtimer_wakeup) 
   0,0% (  0,3)        kcryptd_io : blk_plug_device (blk_unplug_timeout) 
   0,0% (  0,3)   gnome-power-man : schedule_timeout (process_timeout) 
   0,0% (  0,2)      <kernel IPI> : TLB shootdowns 
   0,0% (  0,2)   operapluginclea : schedule_timeout (process_timeout) 
   0,0% (  0,2)   update-notifier : schedule_timeout (process_timeout) 
   0,0% (  0,1)         iwl4965/0 : sta_info_start (sta_info_cleanup) 
   0,0% (  0,1)          metacity : schedule_timeout (process_timeout) 
   0,0% (  0,1)     <kernel core> : inet_twsk_schedule (inet_twdr_hangman) 
   0,0% (  0,1)     <kernel core> : page_writeback_init (wb_timer_fn) 
   0,0% (  0,1)           kcryptd : blk_plug_device (blk_unplug_timeout) 
   0,0% (  0,1)     <kernel core> : ip_rt_init (delayed_work_timer_fn) 
   0,0% (  0,1)       ksoftirqd/0 : ndisc_dst_alloc (fib6_run_gc) 
   0,0% (  0,1)   gnome-volume-ma : schedule_timeout (process_timeout)