Hello. I have the following issue. On my laptop (Sony vaio VPCF11M1R) hard disk slows down dramatically from time to time (Timing cached reads: 2 MB in 2.08 seconds = 982.80 kB/sec). I suspect this is related to battery charging level. It looks like there is a system process that turns HDD to such mode. What can be done about it? Please, help. Ubuntu version 12.04. Thank you.