Do you mean a (blank) new tab, or any new tab even if you are opening a link or bookmark into a new tab?

If it occurs with a (blank) new tab, what is your new tab page set to? You can double-check here:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful.

(2) In the search box above the list, type or paste newtab and pause while the list is filtered

(3) If the browser.newtab.url preference is bolded and "user set" to something other than about:newtab, you could try resetting it to the default to see whether that makes any difference.

Does Firefox work more normally in its Safe Mode? That's a standard diagnostic tool to deactivate extensions and some advanced features of Firefox. More info: Diagnose Firefox issues using Troubleshoot Mode.

You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" button > Restart with Add-ons Disabled
• Help menu > Restart with Add-ons Disabled

and OK the restart.

A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any improvement?

I have temporarily solved the problem by downgrading Firefox to version 28.0. I noticed the Centos has held their version of Firefox to 38.2, perhaps for similar issue.

There is an enormous difference between Firefox 28.0, a version from 17 months ago, and 38.2, which is the current Extended Service Release (ESR) version. To learn more about ESR, see: http://www.mozilla.org/firefox/organizations/

Downgrading to Firefox 28.0 did not help. I did a clean install in a VMWare Fusion virtual machine of Linux Mint 17.2 Cinnamon and I still have the same problem. It is not specific to opening tabs, just opening a random website causes Firefox to hijack the cpu, then freeze the system and finally crash and reboot.

What is the threshold of the resources?

• Firefox uses too much memory or CPU resources - How to fix