My browser tabs in firefox and chrome crashes frequently in ubuntu? Is there any issue with the memory module, because other programs also show segmentation fault in the crash logs?

Depends on how big your memory is. Maybe try increasing Swap partition size or upgrade your stick. I've got 4GB DDR3 2GB swap and it holds pretty strong. Maybe 50-100% the size of RAM allotted to swap somehow helps incase you have below 8 gigs of RAM. If it's 8+ gigs then something is wrong with your system I'd say. You'd of course have tried rebooting but check if you run scripts during init or during session that does malloc and similar stuffs. These can properly break your system. Identify and correct/ delete such scripts

@silverstar I have got 8 gigs of RAM.

@wolt memtests are failing.