FREE UPGRADE! Happens when they run out sometimes. You can check system info to see what exact CPU is installed.

Dell did that to me once, and it had some thicc paste under it lol.

3600 was $150 regularly at microcenter. Later, the 5k/5600x came out, was in short supply, and the hype from the better performing 5k series got the prices on 3k to go up lol. Soon after, the 3600 went back up to $200.

I ended up doing a bunch of 9700k builds because they were on sale for $200 at MC. Better for gaming than the 3k series.

Depends on usage, but you should be fine for a long time. I had a 9700k, and that was great besides the heat. 12400 is a bit faster, and runs cooler, but most the time you won’t notice it unless you compare FPS, or do CPU intensive tasks. At 1080p gaming, some games will get a noticeable boost, but others not so much. The differences shrink at higher resolutions. If you are a gamer, try to look for benchmarks with your video card, and a 12400, and compare them to what your 9600k is getting in the games you play at the same resolution. That should help a lot with your decision.

In general, most any modern CPU will do all the basics, and can be paired with any low to mid range video card for gaming. If you don’t push games, or do anything really CPU intensive, then even a CPU like your 9600k can be fine for around a decade. Just keep your OS clean. My old 4770k only retired a couple years back due to user error lol. Things like faster USB (type c), better wifi, NVME, etc were more noticeable than going from my 4770k to 9700k for basic use.

I got my 12400 for $140 when it came out for an ITX build. At the time it cost less with an ITX mobo than just the ITX mobo for my 10700k, and it performed around the same as that 8 core with much less heat. Paired it with a B660, RTX 3070, and have had no real issues. 12400’s been quiet, efficient, and powerful enough, but I’m not chasing max FPS, or doing really intensive stuff with my pc.

Contact Intel. They are usually very good at taking care of their customers.