The speed differences (in terms of rendering) can usually be greatly affected by render settings. Simply saying it's 10 times slower... MAY... be comparing apples and oranges. (speaking of SR2 BTW) and I have and USE both P4 and P5. I also think your point shows that some P4 users simply shrank in the face of P5's added complexity and thats why they went back to the comfortable old P4. (Hey I'm not slamming em... I refuse to upgrade from Truespace 4 cuz I hate the newer versions' interfaces.) If your happy with what P4 does theres no reason to upgrade, if you feel your art needs ray tracing and advanced shaders, then P5 is the only way, at least until DS matures into a complete solution.