Windows Aero causes massive lag and stuttering on HD5450

Hello folks,
I have a HD540 card on my Windows 7 64bit machine, connected to a CRT TV using a vga to scart converter. I was able to get a stable 15khz signal to show an image on the crt.

But, enabling Windows Aero to get proper Vsync (I also watch videos and such media on my TV) the system starts to lag heavily, sometimes gets unusable how much it lags. No matter the application, even the deskop and mouse pointer show sings of slugishness and lag. Sometimes it lags, but sometimes it doesn't, it literally starts and stops on random ocassions. Most notably it shows inside of fullscreen programs (like "Kodi") where it automatically starts to lag when the program is opened. Disabling Windows Aero disabled Vsync aswell, and that's where I start getting screen tearing when watching something that has less than 50FPS (PAL).

I  tried enabling Vsync inside of the radeon settings, but it only shows effect on Kodi, other programs like VLC, and web browser players take no advantage of the setting.

I don't notice any lag when I select a resolution with 25Hz, but that's really pointless, since some videos and most classic games (like on gamecube) run on 50fps+.

The resolution I choose doesn't matter, I am running mostly 50Hz interlaced.
Things I tried to do are:
- completely uninstall standard AMD drivers, and install the drivers given from the setup.exe in the crtemudriver archive
- tried running the Windows interlace patcher (can't due to unsupported kernel)
- tried both Catalyst and Crimson setups
- tried using Catalyst 16.2.1
- tried using latest amd drivers

Nothing resulted in a fix.
Here's the dxgmms.sys file for the Intelace patcher, that program might be a fix (https://www33.zippyshare.com/v/gsxKoySP/file.html).
Hopefully someone will be able to help me out.