for a start you may actually want to use the software designed for DFI's monitoring chip
, ITE Smart Guardian. it should be included on your driver disc. 50c is acceptable
though too high for my liking. perhaps you could remount the chipset HSF with some Arctic Silver. it's probably mainly because your graphics card no doubt hangs over the chipset fan. it is possible to put the card in the second slot (if you enable SLI the slot will run at 8X) which will probably drop your temps a few degrees in my experience. however in my experience this can cause a significant delay in POST/boot.