my browsers hate my Mac

[cellio]

For the past couple weeks -- but not before then -- both Firefox and Chrome have been randomly seizing up on me on my Mac at home (running Snow Leopard). When this happens, first that application and then (about 10-15 seconds later) the entire machine become unresponsive, presenting the spinning beachball of doom. After a minute or so, but occasionally longer, things go back to normal. Sometimes I see a Chrome pop-up about an unresponsive site flash by. When this happens and I can watch in the Activity Monitor, neither CPU nor memory is pegged. Sometimes this happens once a day; sometimes it happens a couple times in an hour. It's becoming a pretty big usability problem.

All browsers are up to date (and not beta versions). This doesn't happen on my work machine (Win7). Dani says this happens to him on his brand-new iMac with maxed-out memory, but only with Firefox. (So he uses Chrome -- problem solved.) For me on my dusty old Mac Mini, it's happening with both browsers. I can't figure out what changed -- why is this happening now?

Googling told me that disabling the Flash player extension/addon/plugin/whatever could fix this, but it didn't. I've also looked through extensions and disabled anything I'm not actively using; it's pretty bare-bones. I do have several userscripts, none written by me, but I don't see anything glaringly suspicious in their code. I've already disabled the ones I can live without at least for a while, but a couple of them really are critical. I'm not finding any help on the Apple forums.

I've been thinking about upgrading my hardware anyway, as even before this started my Mac was starting to get sluggish sometimes. I bought it in something like 2009, so that's not too surprising. But the Mini hasn't been updated since October 2014, so this is the wrong time to buy -- something better should be coming before too much longer.

Meanwhile, I'd like to diagnose and fix this problem. But I'm out of ideas. :-(

Comments

[siderea]

I have a similar problem, which I've had for a long time, with my MacBookPro on Snow Leopard. Happens with both Firefox and Chromium, and also Safari. Disabling Flash helped, but didn't fix the problem. [ETA2: And, like in your case, Activity Monitor doesn't report that memory is maxed out.]

Certain js-heavy pages left open (e.g. any Google or Bing search results) degrade the performance of the whole machine slowly over time, and only restarting the browser gets it back to baseline; after a while even that is insufficient, and I have to reboot the device.

If I'm trying to load web pages when my virus checker attempts to update, the browser starts beachballing like whoa.

I've noticed that performance seems to degrade (and we're talking about browser tendency to beach-ball) directly with processor temperature. I am running smcFanControl, so I have constant visual report of my processors' temps. I mean, right now, they're at 120 and 122 F, which lets me know even before I try to do much that the browsers will be sluggish, if not quite beach-balling.

ETA: Oh, and I've given in and installed NoScript on FF, which also helps a lot.