PowerTOP 1.9    (C) 2007 Intel Corporation 

Collecting data for 15 seconds 
< Detailed C-state information is not available.>
P-states (frequencies)
Wakeups-from-idle per second :  5.3	interval: 15.0s
Power usage (ACPI estimate): 15.4W (3.2 hours) 
Top causes for wakeups:
  22.7% (  1.0)       <interrupt> : nvidia 
  22.7% (  1.0)              Xorg : nv_start_rc_timer (nv_kern_rc_timer) 
  10.6% (  0.5)       <interrupt> : ahci 
   9.1% (  0.4)      <kernel IPI> : Rescheduling interrupts 
   7.6% (  0.3)           kcryptd : blk_plug_device (blk_unplug_timeout) 
   6.1% (  0.3)              Xorg : schedule_timeout (process_timeout) 
   6.1% (  0.3)     <kernel core> : neigh_table_init_no_netlink (neigh_periodic_timer) 
   3.0% (  0.1)       <interrupt> : PS/2 keyboard/mouse/touchpad 
   3.0% (  0.1)   <kernel module> : neigh_table_init_no_netlink (neigh_periodic_timer) 
   3.0% (  0.1)       <interrupt> : extra timer interrupt 
   1.5% (  0.1)     <kernel core> : end_that_request_last (laptop_timer_fn) 
   1.5% (  0.1)           pdflush : do_journal_end (delayed_work_timer_fn) 
   1.5% (  0.1)   <kernel module> : sta_info_start (sta_info_cleanup) 
   1.5% (  0.1)     <kernel core> : page_writeback_init (wb_timer_fn) 

Suggestion: Enable SATA ALPM link power management via: 
  echo min_power > /sys/class/scsi_host/host0/link_power_management_policy
or press the S key.