I just recieved a terrain mesh with over 16M polys. I can open it and mess around the scene quite well since I'm on a really decent PC. But I'm trying to decimate it (using the modifier itself) and my PC just crashes. It gets stuck for a while and then the sound and signal dies and PC freezes forever. I haven't tried letting it frozen for more than 10min but since the sound on the PC dies I'm assuming it won't get out of the dead lock.
I don't think I'm recieving a less hi-poly version of that mesh, so I don't know what to do.