Is it worth upgrading for performance gains if you have a 2500k or newer Intel quad core? No. Is it worth upgrading for the better feature set? Depends if you want the new toys you won't have on something old like a 2500k system like for example M.2 Nvme support, USB 3.1 Type-C Gen2, being allowed to use 4K Netflix and so on, if you are not going to use them, then no. But if you are going to upgrade anyway due to old hardware failing / for the sake of it then may as well opt for the newest tech. Just my opinion of course.