2x is still not right. Something is choking the transfer. Have you beenn into Device Manager to look at the Hard Drive (Write Cache enabled) and in Advanced Settings, as already suggested, DMA mode?

For the burner, you have to be careful with DMA as there are potential IDE clashes. But at least try and change the burner from PIO (which it probably is) to DMA because you can always change it back.

Halving your memory (to what) puts a strain on Windows paging. So it may be linked.