As the title says, I have this flickering issue with the fog of war in Icewind Dale 2 whenever I'm scrolling around with my mouse. I've tried both integrated and nVidia graphics, various fixes etc. but haven't had much luck. It's literally the only thing that needs fixing before I can start enjoying my playthrough. Any new insights lately? Tips are very welcome.

You're talking about the original game, not EE, right?

I had the same problem on Windows 7. In the game's settings (the one outside the game with a separate exe) disable hardware acceleration or enable it if it is disabled. I forgot which one worked for me.

Ah, I see. I didn't notice it was 2. The flicker fix for me by disable hardware acceleration was for 1.

I installed the Microsoft DirectX SDK yesterday evening and suffice to say it doesn't exactly work like a charm. Also tried following the steps outlined in this guide here: https://zeckul.wordpress.com/2012/01/10/icewind-dale-2-ultimate-installation-guide/
I wish someone could furnish insight into the root cause of the blocky-esque fog. Right now it feels like I'm troubleshooting blindfolded.

Did you try some of the in-game graphics options?

Oh yes, I tried and then some. Messed with the .ini files before reinstalling the game too. I'm at my wits' end trying to pinpoint the cause of the visual artifacts. I know it's an old game but watching that stuff flicker as you scroll around is such an eyesore that it makes me quit not long afterwards. I'm going to keep trying though. It has me intrigued and I probably won't quit looking for a fix until the bug's gleefully squashed.

Good luck. One final thing I can suggest is did you try a lower resolution?

Try disabling AA and Anisotropic filtering in your graphics card control panel for IWD 2.