If I go AMD, how does something like the Ryzen 5 3400G look?
https://www.amd.com/en/products/apu/amd-ryzen-5-3400g

Do you not intend to use a dedicated GPU? You mentioned you want to use a nVidia card.

All G version ryzen cpus have integrated graphics which you won't need.

As an advice, try and look at the ryzen 3600 or 3700.

Actually, I explicitly said that I do *not* want an nVidia card; unlike Intel and AMD, nVidia does not release the source code to their Linux drivers, and as such, one can't easily update the kernel while still having GPU acceleration, particularly if one decides to try out an rc kernel or some other non-mainline kernel.

Not that I know of. I use Wikichip
Good enough. It's a little faster than what you have at the moment.

That's what I get for posting while on the train heading home. :(

Any other thoughts?

I don't know the prices where you live, but here the 3400G sits between 2600 and a 3600 in cost.

If you can use the graphic card you have now or have access to a cheap one (your games don't seem to be much demanding), I highly recommend a 2600 (or a 3600 if you have the money) for the long haul.

Why? The 3400 has lower performance due to VERY small cache, 4MB L3, the 2600 has 16MB L3, and 3600 has 32MB. The 2600 also has more cores and threads. All of this is important when crunching a lot of data.

Even though the 2600 is 200-300Mhz lower than 3400G, it doesn't matter, and you can easily OC (with a B450 chipset) that little gap without straining the system or cause a lot of wattage.

https://www.amd.com/en/products/cpu/amd-ryzen-5-2600
https://www.amd.com/en/products/cpu/amd-ryzen-5-3600

My current GPU is an integrated graphics card, so I couldn't re-use it without re-using the CPU, and as I mentioned, it is of the generation that is severely affected by the mitigation I mentioned, so I would rather not re-use it.

Make sure to check for your future motherboard to have IOMMU support implemented in BIOS.
Your CPU and mobo's chipset might have hardware virtualization support, but if your mobo doesn't have this enabled on BIOS level it just won't work.

In the past (amd bulldozer/piledriver cpu era) some amd mobos had no ACPI IVRS tables in BIOS, which resulted in IOMMU not working.
To check for present ACPI IVRS tables in bios one had to execute following command in console:
$ cat /sys/firmware/acpi/tables/IVRS

I think you'll need to google for "IOMMU groups".
Not familiar with current hardware, tbh.

Do not buy anything with less than 6 cores, if you want to build a future-proof PC.
Even things like system boot are utilizing multiple cores now (systemd), not to mention compilation process (make -j).
And integrated graphics is not worth buying for gaming.

Here's the sample config (~ 700$ build, w/o case and PSU, 64Gb RAM), for OP and anyone interested (didn't check the mobo for IOMMU stuff though):
MSI GeForce GTX1650 SUPER VENTUS XS OC 4.0 GB OC 152,94 €
MSI B450 TOMAHAWK MAX 90,67 €
AMD Ryzen 7 2700X 8 core (Octa Core) CPU with 3.70 GHz 148,73 €
G.Skill Aegis 16GB DDR4 16GIS RAM 48,73 € x4
HP EX920 SSD SATA3 M.2 NVMe 512GB 61,34 €

GTX1650 SUPER videocard can be changed to RX 5500XT or RX 580.
Also, there are tests (including gaming tests) for videocards on Phoronix (site dedicated to GNU/Linux).

PS: Last, but not least, PCMasterRace Reddit: https://www.reddit.com/r/pcmasterrace/wiki/builds
There are different gaming builds for several budget groups (500$, 750$, 1000$, 1500$). Good starting point, if you do not know where to begin.

Economically it makes no sense compared to what you gain.

The Ryzen IGP is more than capable of handling games. With the amount you save, you can buy a that RTX/Vega card in 6-12-18 months that is now cheaper (or get it on sale). It all depends on the money vs performance, and like I wrote, paying too much just because of 8 seconds less or 8 more fps isn't worth it.

Other than that I actually agree on 6 cores today, since it's more future proof and the price isn't bad.

[Modded by Sanscript: Yes, bad me, I offended a touchy gamer]

Ryzen 3000 series is hot. Don't grab the 2000 series. For the same price (even with the steep discounts), you'll end up faster and leaner for the same price.

If steer clear of Intel for the next year or two. They have a major shortage right now, so their chips are expensive for what you get. They are focusing on server processors to get something out the door.

Interested had also screwed up quite significantly. They had a hard time getting their lithography down a step and made all their gains in more thermal output and optimizing the processor with really smart circuitry which, unfortunately, is riddled with vulnerabilities. Their newest generation of professors actually runs shower than their previous generation (except in AI, which sees a big gain).

So, Ryzen 5 3600 is probably where I'd land. Weird, right? (I've been an Intel fanboy for decades)

So, looks like I should look at the 3400g rather than the 2400g, then.

(I still think I'd prefer integrated graphics at this point.)

As a side note, while I have been using just Intel CPUs recently (except for my phone's and Raspberry Pis' ARM CPUs, of course), I actually did use an AMD machine for many years. I bought it during the Pentium 4 era, as I believe at that point Intel's CPUs were rather inefficient; I believe I may have gotten one of the last AMD CPUs to not support long mode. (Long mode is the feature that indicates that the x86 CPU is 64-bit capable.)

Good choice, the performance gain from 2400G to 3400G is staggering compared to the 5-10 bucks that sits between them.

I myself have been crunching on a A10-7850K+RX480 computer and went for a 2600 myself since the price jump of 60%+ up to 3600 is not worth it compared to the performance gain. Would have gone for the 3400G myself if I didn't want to chew a bit longer on the RX480.

If you can hold out until Summer, AMD should release new APUs with Navi graphics. If not, 3400G is the best they have to offer right now.

You want to switch from a still pretty powerful 4 core cpu (i5-4670) to a 4 core cpu (Ryzen 5 3400G).
Why? Because of low integrated graphics performance of i5-4670?

If that is the case, just buy a decent AMD videocard and a USB 3.0 PCI-E expansion card and your requirements will be met.