Why, if absolutely everything except Android emulation (desktop Linux and Windows emulation work fine) and recent games (in which I am not interested) work perfectly? I've just replaced my HDD with an SSD a couple of years ago and it feels like a new PC again. I never experience even slightest discomfort when I'm not trying to emulate Android.
> Because emulation is a heavy operation. Be realistic.
Then why is desktop Linux and Windows emulation not nearly as slow? Windows 7+ emulation is slightly slow, especially running VisualStudio on an emulated Windows7 is painfully slow (while perfectly swift on non-emulated) but still usable if you have enough patience (Android emulation is absolutely unusable). Emulated (VirtualBox on a Linux host) Windows XP runs even faster than on bare metal.
> Also I don't believe that PC isn't painful to use for everything else. I had a core2duo a while back and it was slowish back then.
You probably did something wrong. It's not just painless, it's perfectly swift (both with the latest KDE Plasma and with Windows 7). I have a modern PC at the office (late pre-Ryzen AMD, 8GB RAM, Win10) and its perceived performance is the same. It even feels more slow (less responsive) than the Core2Duo occasionally but I blame that to Windows10.
Of course I only mean basic tasks like browsing the web, watching videos (1080p or less), juggling files and writing code (VisualStudio, IntelliJ) for small projects. Obviously any modern CPU will beat Core2Duo in video transcoding, modern games etc.
Even a current i5 is more than double as fast per core, and likely has 12 threads instead of 2. So as a roundabout figure let's say 8x the effective speed.
VT-D makes your Core2Duo better able to emulate Windows or Linux in hardware, but not Android.
Like I said, I don't believe that a Core2Duo isn't slow for everything you mentioned. I had one at home. I wasn't doing anything wrong - I know how fast it isn't - we had hundreds at my work. Have you noticed that other commenters are saying the same thing about Core2Duo speed as me? You must have more patience to wait for your PC than myself and the other commenters.
The reason I replaced my Core2Duo was because it was slow, and I replaced it around 8 years ago!
Core2Duo was released over 13 years ago, and discontinued over 7 years ago.
Time to think about upgrading before complaining about performance issues. Especially for emulation.