The LoD (Level of Detail) setting for vanilla AC2 is terrible, and you would experience a lot of texture popping (streaming) issues. Basically everything looks like hell from 5 in-game meters away. You cannot change this using normal means, incl. through GPU driver control panels.

But! We now have a fix from the almighty modding community:
https://www.moddb.com/mods/assassins-creed-2-visual-fixup-mod

The use is dead simple:
1. Download this mod;
2. Extract anywhere (you probably need to whitelist this mod in your anti-virus software);
3. Run AC2 as you normally would;
4. Run AC2VFM.EXE;
5. Alt-tab back in game and press F2 to enable high resolution shadows and F3 to enable higher draw distances - and thus fix the texture issue - Take note! If you find F3 not working, just try to press again very BRIEFLY. It's probably because you have pressed it for too long and the program interprets your input as twice (toggled on and off) .

Credit goes to mod creator Bucket5! And I also recommed giving this mod from renanthevampire a go: https://www.moddb.com/mods/assassins-creed-2-retexture-project.

中文版：
从这里下载：https://www.moddb.com/mods/assassins-creed-2-visual-fixup-mod
解压到任意位置；先运行游戏，切出运行AC2VFM.EXE，切回游戏短促地按F2和F3各一次。如果按F3画质没改善，说明按键时间长了，被程序解读为按了两次，这种情况下再按一次。杀毒软件会误报，要设置为例外。