191x7

If the system doesn't boot with a different CPU, then it's not the CPU. You need to try with a different GPU, ask a friend or someone, it can be old or weak - it's just needed to see if you get a picture or the same issues persist.

Which exact 4080? Latest Firmware (vBios)? Latest monitor driver installed?

What's your resolution, which monitor? Also, the 5800XT hasn't been released, there are just a 5800X and a 5800X3D. AMD is supposedly releasing AM4 XT CPU-s soon. Do not use UserBenchmark for anything meaningful, that tool and site are almost useless and misleading. Looking at the system, it's quite optimized for 1080p, maybe a newer/stronger GPU would do better, but I wouldn't recommend above a 3060Ti/4060 or Radeon 6600XT/6650XT/7600/7600XT/6700 for 1080p with a 5800X. A 5700X3D or 5800X3D could do a 4070 or RX 6800/7700XT. If you're on 1440p, the 5800X can handle up to RX 6800XT/7800XT or RTX 4070 SUper, 4070Ti.

The only valid AM4 options for gaming are the 5700X, 5700X3D and 5800X3D. And they are for upgrading older Am4 systems. Amd is supposedly releasing AM4 XT CPU-s soon, meaning higher clocked better binned Ryzen 5000 non-x3d parts.

It's a good board. But I'd avoid Gigabyte (personal experiences).

And, based on that information, it makes no sense to upgrade to Zen 4 unless a 7900 or higher is needed for productivity. Just get a 5700X3D or 5800X3D and a better cooler if you're using the box cooler that came with the 3700X. Update the Bios to the latest, install the new CPU and you're golden.

What do you have now? If you have a decent AM4 board, the Ryzen 5800X3D performs like a 7700X and it wouldn't require you to change the RAM and the MBO.

The 5800X shouldn't be 260, that's the price of a 5800X3D.

First, clear the CMOS by unplugging the PC from power, removing the CR2032 battery, pressing the case power button, waiting a couple minutes, putting the battery back in, plugging the power and trying to turn on the PC. Connecting the monitor to the motherboard can't produce a picture because the Ryzen 3600 does not have an integrated graphics chip. Only the CPU-s ending with a G have integrated graphics on AM4, for example the 5600G or 2400G.

Without having parts you can't properly test. Maybe take the PC to a competent repair shop? What are the exact issues you are experiencing?

Blue Screens do not mean CPU issues, they can be caused by many different things. Did your CPU completely stop working but the board works with a different CPU?

Didn't you flash one of the newer Bioses before your CPU died? Also, are you sure the 3600 died on you, have you tried it in a different PC?

You can do better for about 310-350 GBP. Ryzen 5700X3D to 5800X3D 230-250 GBP 2X8GB DDR4 3200 Corsair LPX 40 GBP Peerless Assassin 120 SE 40 GBP.

You can get a 5800X3D and use the same platform. This will probably eliminate any bottleneck on 1440p. It performs like a 7600X to a 7700X but sometimes it beats even the 7700X. Your other option is to change the platform and go with something like a Zen5 CPU (7700, 7800X3D) with a B650 board and ddr5 RAM.

If you can afford a 7900X3D you can probably afford a 7950X. The 7950X is way better for both productivity and gaming. Because it has 8 cores per CCD and two CCD-s while the 7900, 7900X, and 7900X3D all have 2 CCD-s with 6 cores and the latency between the CCD-s is high. The issue with a 7900X3D and 7950X3D is that only one of the CCD-s has the 3D cache and both Windows and games have a hard time scheduling the software/game threads to the correct cores. And disabling the non-3D cache CCD for gaming makes the 7900X3D a 7600X3D (although a 7600X3D doesn't exist yet) and the 7950X3D becomes a 7800X3D, There is another option for you, the 7900 non-X non-X3D. Roughly the 7900X performance with a lower power draw and less heat. The 7950X is two 7700X, so its game performance matches the 7700X but it can be higher if the game can use more than 8 cores (extremely rare at this time). And yes, the X3D chips have lower clocks compared to the non-X3D. So if a game doesn't know how to properly utilize the architecture containing the large 3D cache, the X3D-s are weaker than the non-X3D.

You are confusing the 5000 series and the 7000 series.

Yeah but once you consider you need new ram and a new cpu the only thing standing in the way of ddr5 becomes the motherboard, and then it's better to go with a new platform...

You can do a few upgrades; a) a completely new platform like a Ryzen 7000 series CPU, 32GB DDR5, and a B650 board b) 32GB DDR4 3600 RAM, keeping the 3900X CPU c) DDR4 3600 and a 5700X d) DDR4 3200 and a 5800X3D 2133 is simply too slow for Zen 2 and Zen 3, limits the CPU a lot.

B550 doesn't officially support Zen+ so you have to either get a B450 or X570. Although, I've seen B550 working with Zen+...

You should update to the latest version. https://www.msi.com/Motherboard/MPG-X570-GAMING-PRO-CARBON-WIFI/support So your RAM isn't 3000 but 2133? Or is some of your RAM 3000 and some 2133 and thus it works on 2133 together?

Which motherboard do you have? Using the latest Bios?

His post states 3000 and that's fine for a 5800X3D. With a regular Zen3 I'd aim for 3333, 3400, 3600 or 3800 RAM but for an X3D 2933/3000/3200 is just fine. His signature shows an i7 6700K and ddr4 2133, maybe that was the previous machine, and maybe now he's running DDR4 3000 at 2133 because the XMP (DOCP) profiles aren't loaded? @Sumtinwon is your DOCP (XMP) profile loaded in the Bios? If you have DDR4 3000 but running JEDEC spec 2133 you are severely limiting the 3900X. Please check your Bios settings. And add a few CPU-Z screenshots here.

Or they could add, at least, the Fritz Chess benchmark tool that comes with Fritz Chess.

On top of the mentioned tools I'd add Hard Disk Sentinel, HDTune and the tools in the Linux distro named Parted Magic.

They do. I switched from a 5900X to a 5800X3D because the 5900X was bottlenecking my 6950XT.