layers.offmainthreadcomposition.force-disabled

Sorry to hear about the crashes. If you are getting the Mozilla Crash Reporter form, your Firefox may have logged some data that would help track down the cause of the problem. You can submit that data to Mozilla and share it with forum volunteers to see whether it points to the solution. Please check the support article "[[Firefox crashes - asking for support]]" for steps to get those crash report IDs from the about:crashes page, and then post some of the recent ones here. I suspect, based on my own experience, that it could indicate Firefox is running out of memory allocation. Around that time, is Firefox becoming sluggish and showing NOT RESPONDING for 30-60 seconds at a time? Facebook causes Firefox to consume a huge amount of memory because of the continuous/endless loading of content into the tab as you scroll down, so that why I thought of memory first. In some cases, Firefox is not completely compatible with your graphics card/chipset driver software, and that causes blackouts. In some cases, the black clears as you mouse around on the page, or if you switch to another tab and then back again. If that is more similar to your symptoms than the low memory scenario, \and since you have Nvidia, you might try this: As an experiment, try disabling OMTC. This feature was added in Firefox 33, but seems to be acting up with Nvidia cards in Firefox 48 for some users. (0) Select and copy the following new preference name: layers.offmainthreadcomposition.force-disabled (1) In a new tab, type or paste '''about:config''' in the address bar and press Enter. Click the button promising to be careful. (2) In the search box above the list, type or paste '''layers.off''' and pause while the list is filtered (3) Right-click a blank area of the page, click New, then Boolean (4) Paste the preference name, then click OK (5) Select true, then click OK ''The preference should appear in the list, bolded, and user set to true. If you need to remove this later, right-click > Reset it'' I think you probably need to restart Firefox before that takes effect.