Inspiron 3668 CPU Upgrade

The Inspiron 3668 has the Intel H110 chipset on the motherboard.

Doesn't look like the i7-8700k supports that chipset....

And just to add the price of the i7 8700K is around $450-500 for a new CPU (here). The performance increase over the i7-7700 is around 15%. So there is not a huge performance increase to be realized. The i7-7700 was a very good CPU and still performs well in today's latest games.

Re: But it is the same socket as the i7-8700k. Can I put one of those in or something else? 

the 8th gen coffee lake cpu are only supported by 300 series chipset such as Z370, H370 etc.  "Although desktop Coffee Lake processors use the same physical LGA 1151 socket as Skylake and Kaby Lake (for intel 6th and 7th gen cpu supported by 100/200 series chipset), the pinout is electrically incompatible with these older processors and motherboards"

“When compared, the Coffee Lake processors have different pins compared to Kaby Lake.”

i7-7700 (4 core) -> i7-8700 (6 core)

• VSS (Ground): 377 -> 391 (+14)
• VCC (Power): 128 -> 146 (+18)
• RSVD: 46 ->25

Coffee Lake processors use a vastly different pin configuration compared to previous generation processors, and as such, there is no backward compatibility with 200 or 100 series motherboards.

My problem is that i7-7700 is not compatible with Windows 11.

I like my Inspiron 3668 and it never missed a bit.

Do I really need to buy a new PC to support Windows 11.

Yeah, not buying a new PC.  If my brother's system can't run MSWin11, it already has a Linux partition on it (except I still need to kick Fedora off of it and re-install Linux Mint).