Undo is too slow

I kinda hope I'm the 1000th person to mention this so it'll get removed and marked as 'stop annoying us with this request already'. But... seriously, 10-20 seconds for an undo? Never in my days of using 3d software has this been the case with the exception of maybe doing a heavy operation that in itself took a few minutes to calculate. Udoing something like that, fine, it's a one off. But I have a scene that's got two lights, half a dozen meshes, at 3m polys and each undo (like moving an object) takes a good ten seconds. I can get it down to 3-5 seconds if I'm in solid viewport shading mode or wireframe.