Artyomka

Also try unplugging all of the fans but the cpu.

If you reconfigure it again - yes.

Will you notice a performance bump over raid 0 HDDs - Yes. A noticeable one. WIll your HDDs suffer a performance loos in SATA 3GB/s over SATA 6GB/s? - No. Hard Drives cannot saturate even sata 3GB/s. There is a huge problem, though. There is a good chance those 6 GB ports do not run through a chipset, but through a dedicated SATA controller, if the mobo is old. You may loose raid if you reconnect them in other ports. Or even if it is a chipset raid you may still lose it if you reconnect them in other ports. Huge warning there.

I stronly suggest you go for a Socket 1366 or better a 2011 for a cheap home server. Old server tech drains power and get those electrical bills fat, so you are not saving much in terms of money in the long run.

It depends on what you will do with all the cores, 4 is still more than enough for gaming. If you don't do video editing\3D rendering\FHD 60fps streaming every day you will not feel any difference between 4 and 10+ cores. If you do then go for 6-8 cores, the sweet spot in price is there.

With Ryzen I would go for ram without thinking twice.

I do not think it is even possible to run nvme storage in sata mode. Use Crystaldiskinfo to determine in which mode the ssd is currently working, it could be running in pci-e 2.0 or even 1.1, thus the speed drop. Post a screenshot of the Crystaldiskinfo if possible.

vCPU are like time slots of your CPU, not physical cores. The more you allocate to a VM the more cpu time it can get. I suggest you allocate 2 vCPU to your VM and just add more if you see that the VM is not responsive enough.

Please check in BIOS that the intergrated GPU did not alocate itself these 4.5 gigs. If you you have a dedicated graphics card then please disable the cpu integrated one completely in BIOS. This should get you the ram back.

It has some decent hardware inside, it should be enough to handle a VPN server. If not just switch to NAS.

It should definitely be a router. Makes things easier.

A lot of viruses detect that task manager is running and stop the moment you open it. Try using something like System Explorer to see running tasks.

These are super old servers, I get that they are cheap but they are power hungry and most likely very loud. You should go with something less old, with xeon x56** or better. And look for a tower server if you don't have rack at home. For the system you can use anything you like, as long at it works for you. But you will probably have driver issues if you try to install windows 7 or 10 on these server. And you need a Windows pro version to run on a dual socket server.

It does look like a broken monitor. Try plugging it to another system if possible to check it.

Go for a home server with FreeNAS or unraid. You can get a small case with 4+ drive bays (I would recommend external drive bays for easy access) and use a celeron+itx mobo. If you go with a non embedded CPU motherboard you can even upgrade it to a powerful home server after with an i5 or i7. If you don't want to bother and want things to just work go with the first option. how is it likely for a raid control to fail? - Depends. But it's super easy to replace with a new one of the same model, it will just read the raid topology and continue from where the old read controller left. whats better - a raid card or use the onboard raid controller on a motherboard - If you go with raid 5 or 6 it is definitely a raid card. If takes DAYS to rebuild raid 5 on an integrated raid. But double check if the controller has hardware raid 5 acceleration. which raid config is best for safty? raid 1, 1+0,5,6 - I would go for 10 or 5, depends if I want more storage (5) or read\write (10) speeds.