Minisforum 790S7/795S7, mini-ITX desktop.

16 cores, 32 threads, only a bit less powerful than a desktop Ryzen 7950X or a 14900K, but with a comparatively low power usage.

About 500€ barebones, then you add your own SSD and SO-DIMM RAM.

>My test suite currently runs in ~6 seconds on 9700K

Absolutely nothing. 6 seconds is about the time it will take you to tab to your terminal, press up arrow, find your test task and run it. There's no amount of money that makes it go from 6 to 3, and no world in which there's any value to it.

In addition, upgrading to a 13900K means you're playing the Intel Dance: sockets have (again) changed, in an (again) incompatible manner. So you're looking at, at the very least, a new CPU, a new motherboard, potentially a new cooler, and if you're going too forward with CPUs, new RAM since Intel's Z890 is not DDR4 compatible (and the Z390 was not DDR5 compatible). Or buying an entire new PC.

Since you're behind a socket wall, the reasonable option for an upgrade would rather be a sizeable one, and most likely abandoning Intel to its stupid decisions for a while and instead going for Zen 5 CPUs, which are going to be socket compatible for a good 7 years at least.

I bought https://store.minisforum.com/products/minisforum-um890pro to compile Rust faster than my laptop, with 96 GB RAM and 2x4 TB NVMe as a ZFS mirror. Back before Framework Desktop existed.

It has the 8945HS CPU, the article benchmarks against 8745H which is a little bit slower. It's a very worthy price point to consider, tiny and very quiet.

qwen3:30b-a3b runs locally at 23.25 tokens/sec. I know 395+ chip would about approximately double that, but I'm not quite willing to put $2000 into that upgrade.