Hyperthreading can't actually increase your CPU's power, it merely tries to facilitate page file swapping betwen the RAM and the CPU's caches. Why you're getting only a 50% processor hit is beyond me. I don't use Intel chips... On AMD chips, anyway, the CPU hits as hard as it can, but XP tries to place Bryce on "low priority" when rendering. You have to manually crank it back up to "Normal", and then leave the Task Manager "on top", as even minimizing it will revert Bryce 5 to "Low". But once it's set in "Normal", it will hit about 98% consistently. This is due to Bryce, not XP. In Maya and Rhino the processor acts perfectly normal. In fact, I often turn Maya down a bit so I can actually do something else, besides watch it's tiles magically appear... The OpenGL preview should look fabulous even on a low-end Radeon. We're not talking about Unreal 3 here. There's no Normal mapping or displacement, and no hardware texturing. Compared to what I'm growing used to in Maya, Rhino, and of course UnrealEd, Bryce's OpenGL settings are a frickin joke. Useless. In Rhino, I can fly around in GL preview with a preposterous 60Hz framerate. And I'm using an ANCIENT Nvidia Geforce 4 MX440, 64MB on-card. My Rhino models are vastly more complex than anything that can be made in Bryce alone, too. DAZ may say they were optimizing for Nvidia cards, but if that were the case they would be using Direct X, and not OpenGL. Why anyone still uses OpenGL for any reason is beyond me, completely. And to be honest, at a glance (and not knowing the scene in question), it appears that Bryce 5's GL preview is much better than 5.5's, although both are total garbage. I'm saying DAZ spent about two hours "updating" the GL code. Weak. A 12-year old dabbler in Half Life code could have done better. From my perspective, Bryce 5.5 is shit. No new features. Minor changes. It should have taken them weeks, not months. Not even A month. I fear Bryce has fallen into rookie hands again... Corel was bad enough. Or were they? (cackles!)