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#11
Hmm, maybe you are too much of an expert and tweaked it too much. I am a simple straight forward user running Ubuntu in vBox (with Guest Additions). It is extremely smooth on both Ubuntu and Win7. And I run it on a modest 2.5GHz duo core with 3GBs of RAM of which I allocated 1GB to vBox. I really do not notice vBox when it is running whilst I operate on the host. The same the other way around.
Maybe you want to reduce all the settings to "vanilla" rather than trying to "optimize" it.
Note: forgot to mention that my host system Win7 is installed on a SSD.