Well i know yafray is sposed to be multi threaded, but i dont know if it does or not. Because on their site they say they had problems and took it out… but only for a short while… on an old new post…
So ya. And blender i have no idea about.
Oh, and i mean HyperThreading btw. Not true Duel Core.
Any ideas?
Blender’s internal renderer is multi-threaded, but you have to enable the THREAD button in the render preferences F10.
Yafray is also multi-threaded, and I believe that when you render with Yafray, check blender’s console output. I think there’s a line which Yafray reports back which states how many CPUs/Threads it’s using.
Check that out and let us know your findings.
From my own experience of using Blender on my bro’s 3.0Ghz P4 with Hyperthreading, it does make a difference, but obviously not as much as true dual core.
Happy rendering 
Well for YafRay i enabled “2 CPUs” but that didnt do jack. I know this because when i render my CPU usage never goes above 50%… well 55% if you count my other programs here and there lol.
I havent tried the internal blender render yet, but the YafRay i couldn’t get to render a hyper thread cpu.
3Gig P4 with Hyper
Yup that got it. I didnt see any change when enabling Thread with YafRay, but when doing that with the 2 processors option, it works awesome.
That combined with the special YafRay for P4 (G7), omg it renders so fast!!
Now to figure out the damn recive only shade problem! Argh.