If you have the Jabo's Direct3D version 1.6 plugin, then you need to go to the Options, Configure Graphics Plugin, Advanced, Then check on Copy framebuffer to RDRAM
Make sure you only have it checked when viewing snapshots you took and uncheck after viewing snapshots, otherwise the gameplay could go a bit slow.
And if you have another plugin, just do the same and make sure it has the word framebuffer in it.