I usually do not turn off my pc for weeks. In browser I am running about 20-30 tabs at the same time and I do not want to close it till I decide it is not needed anymore. But in firefox I forced to restart it every 10-12 hours as soon as it starts lagging. No other programs on my pc las. The load of my processor is about 30-40 percent and I have more than 30% of my ram free, so it is not the ardware issues. For example, chrome, at the same time has no lags at all with this kinn of usage. I really like firefox more than chrome and would like to use it, so I would be very grateful for your help!

P.S: There are only 2 addons for ff installed. They are: ABP and FireBug.