[29athrowaway]

I have a VM with Haiku and I can confirm it is indeed very fast.

I am no Haiku expert but the Haiku's window manager does not support window composition and does not use GPU acceleration, right? It is also not modular and cannot be replaced.

You can disable composition on XFWM and make it run a little faster on lower spec hardware. You can also use a WM like i3, Windowmaker or Enlightment.

IMO, XFWM is the right balance between functionality and performance.

[waddlesplash]

The whole point of Haiku is a holistic approach to system design, so no, you cannot easily replace the window manager. You can, however, write "decorator" plugins which draw different window borders, write shortcut plugins for "tiling", etc.

It indeed does not use GPU acceleration; Haiku as a whole does not have 3D drivers either (but there are plans.)