Re: it states I need to make a setting change in the BIOS. I do not think so.  the i7-4790 should be plug n play.  I had a similar 4770 in this model works fine when I swap it in to replace an i3.  the downside of this pc is poor air flow.  for some reason mine has a Dell wireless card that is excruciatingly slow so I just added a wifi usb dongle solves problem. back to your son's upgrade, the cpu upgrade would not bring significant performance boost.  the i5 sits at a sweet spot for gaming.  get a faster gpu is almost always more bang for buck.  no worries if the gpu is faster than 4th gen cpu because you can move it to a faster pc later on.
I'm looking to upgrade my son's gaming PC's CPU to an Intel Core i7-4790 or 4790K. I see on the 4790K documentation, to use the overclocking, the motherboard's chipset needs to be Z97. I don't think that's what I have...I assume it's H81.  Also, it states I need to make a setting change in the BIOS. The PC's specs are: Dell Inspiron 3847 desktop PC towerCPU: Intel Core i5-4460Codename: Haswell-DT RefreshPlatform: Socket H3 (LGA1150)Chipset: Intel H81 (Lynx Point)BIOS date: 5/7/19BIOS version: A11PSU: EVGA BR 700 wattGraphics Card: GTX 1650 SUPER Would this PC be able to use the overclocking feature of the i7-4790K? Thanks.
Inspiron 3847 CPU upgrade: Intel Core i7-4790 or 4790K?