Windows 10 1809 really slow after update

Hello everyone, i recently did a fresh install of Windows 10 Pro 1809 x64, because, after upgrading, i was having very weird problems (MSI afterburner not giving me the option to monitor my cpu temps/speed, really sluggish, really long boots time, etc) I have a Seagate Barracuda 1 TB 7200RPM HDD (bought in October 2018 new), with a 77,5 GB partition with Windows and my programs (50,6 GB free), and a 853 GB partition for my games (629 GB free). I have a WD Blue 1TB 7200 RPM (bought in February 2018 new) which i use to store my movies, VMs and other files. The thing is, after the fresh install, the computer was really fast, like, 1 second to open the file explorer, really snappy to boot, etc. But, when i downloaded the updates, all of that went to hell. The PC is awfully slow again, icons appear blank when booting to desktop until 40 seconds after boot, file explorer is sluggish, the HDD does grinding noises all the time. I know is a HDD, but, my brother's WD Black works faster than mine, and he has really heavy programs (Autocad Suite). I tried:

-Disabling Windows Search and Superfetch service (that helped a bit)

-Disabling programas on boot, except for Windows Defender, Nvidia control panel and Realtek control panel)

-Cleaning junk and defragging with windows defrag utiliy

-Checked S.M.A.R.T (no errors)

-Partitioned the disk in two during Windows installation

-Disabled Spectre and Meltdown patches (more on that later)

-Ran antivirus, antispyware, antimalware, adwcleaner, with no positives

-Uninstalled Windows crapware

-Disabled startup tasks and programs

I really don't know what more can i do, buying an SSD is on the to-do list, but it won't be happening right now, as im saving for an entire new pc. My current specs are:

OS: Windows 10 Pro 1809 x64

CPU: Intel Core i7 2600 (disabled spectre/meltdown, gained a little boost all-around)

Motherboard: Gigabyte GA H61m s2v b3 1.1

RAM: 8 GB DDR3 1333MHz in dual channel (they run at 1600MHz, but, chipset only supports 1333MHz)

GPU: Nvidia Geforce GTX 970

HDD: 1TB Seagate Barracuda 64 MB cache (OS+Games partition)+1TB WD Blue 64 MB cache (no partitions).

There they are, ill post the task manager after i can reboot the machine, as now is being used.

I observe exactly the same, no reboots help

dalchina said:

How much free space do you have on C: ? Is there evidence of paging issues? Task manager screenshot please?

RossoPhantasm- you seem to have plenty.

I have 40 GB free as of today, i have 8 GB of pagefile, both discs are using SATA II but they are SATA III, i understand that that isn't a handicap but i thought that information could help.