Alright there must be some confusion with what I said.
Speed is by no means an issue. This is one of the fastest bog standard 486 you can get. At 120mhz, it can almost run Quake (In fact if you do some finagling with the settings, it's playable)
For the hell of it, I installed WinCiv onto my Windows 3.1 installation (Which is pointless because I have the DOS one installed too).
Before I go onto how it went, I want to say my graphics card is pretty fast. It's a VLB card and can handle rapid changes of frames.
The resolution is set to 1152x864 which is the highest resolution that outputs at 60hz. For no good reason 1024x768 won't work at 60hz, even though it's a supported mode all the way up to 75hz. The card can do 1280x1024, but I do not have a CRT to test that with since the refresh rate is so weird.
Anyways, 1152x864x8, I test WinCiv, and because of the 8bpp mode, it's run out of colours and doesn't look right. I'm not really surprised by this though, and it was a similar issue I had in OS/2. The PCM sound works however.
I do want to say for applications that DO support 256 colours on screen, Windows 3.1 works FINE. The 486 has no problem pushing basic OS functions.
My Trio32 only supports 800x600 with 64k colours on screen, not the 16.7m of an 8bpp colour mode. However, Civilization now works fine on this mode with 0 slowdown. The colours are nice, and the audio works.
So, 800x600x(idk is it 17?) works fine. 0 slowdown for 2D applications. SimTower works fine on these modes, it only slows down on higher resolutions because of the massive sprite and animation count.
I don't know what 486 you were using, maybe an SX-25, but this is a more powerful 486.