svmlegacy

Thats fine. Keep load temps under 90°C.

Clearly if your CPU is being pinned, it's bottlenecking the system. Check your background utilization before blaming the hardware.

The adapter for the M.2 you linked is very confusing to me, and I can't comment on how to use it properly, or if it works the way you're expecting. There's no reason you can't install a 2.5" SATA SSD in place of your old HDD, and do a fresh install.

Link? The title alone doesn't help us much. Obviously it isn't a name brand?

How are you plugging it into USB?

Yes. The HDD will spin down if it isn't accessed for a while. The time is configurable in windows' power settings.

Replacing the thermal paste isn't a bad idea at any rate.

It would be safe to have it OC'd with just the single 8-pin.

It's hard to tell what it means. BDPROCHOT can be asserted for a number of reasons, completely determined by the manufacturer. If the thermal paste has been replaced, perhaps the chipset was missed. Sometimes it can be asserted if the charger is not up to snuff, or the battery is too far gone. As far as the driver issues... I've had lots of issues with windows reinstalling old drivers and messing things up. Uninstall the video driver from device manager, and then let windows update install what it wants to.

Westmere-EP is getting really long in the tooth nowadays. You'll lack core speed, IPC, and AVX instructions. It's okay for productivity workloads, but newer platforms can be a better value. You won't get much for a W3520 on the used market.

Thanks for the clarification. In ThrottleStop, check to see if BiDirectional PROCHOT is being asserted, and disable it there if possible. This will let us know if it's the motherboard or CPU causing this. Also, make sure that the power plan allows 100% CPU utilization.

Chrome isn't the only thing using RAM.

Law enforcement won't help you. That would have been an as-is trade. What does HWiNFO say, regarding clock speeds and throttle reasons? The 7500U isn't a great performer to begin with. Edit: I now realize the BIOS reports the correct speed, while you're monitoring in Windows. It's perfectly normal for the CPU to downclock when it isn't being used hard. What performance plan are you using? Battery saving will put the CPU into cTDP down, which has a base clock of 800 MHz on this chip, as well. High performance mode will unlock a higher power limit will help

Have you tried OC'ing the CPU to see if the performance cleans up? a 3770K has a lot of headroom. If it does clean up, then you know the CPU is what's holding you back, look into a platform upgrade.

Where is the RAM, CPU, Cold Plate, and radiator at? Looks a lot like a paper weight at the moment. (It also might help if you take the plastic film off the front)