Primitive methods play not nice with the jit
Methods that use primitives which we do not implement (many in LargeInteger, for example) run much faster when I remove the <primitive:module:> pragma. I have checked in a 4.5 image that removes all BitBltPlugin, MiscPrimitivesPlugin, and LargeIntegerPlugin usages and runs everything in software. In that image, we compare favourable to Cog (we're mostly faster in graphical demos, for example we're doing ~150fps vs Cog doing ~110 fps with just the bouncing atoms demo on the world), but when the primitives were in, Cog didn't do much better (~200fps), but we did much worse (~8fps). Both of these measurements were obtained with BitBlt in pure Smalltalk, this is just comparing the performance impact of the LargeInteger and MiscPrimitive plugins.