I updated r3dfox from 151.0.2 to r3dfox 151.0.4-hotfix last night and it is unusable. Some of the tabs keep re-downloading the pages opened in them and it was impossible to surf the net at all. I downgraded back to r3dfox 151.0.2 and it is normal again.
Things like this are issue with the app itself and not something we can assist with or fix. I'd wager the just-released 153.0-hotfix version may fix the issue.
Sometimes, the impossible can become possible, if you're awesome!