You have a quite extreme hardware error rate...!!
Thanks for your quick reply, is this most likely to be down to...
cooling?
lack of power? (I'm sure I read in this thread somewhere that normal USB ports dont provide enough power by themselves and they should be put through a powered hub? Are yours in a hub?)
or should I try running it at 0581 or even 0781 just to see if it changes the HW rate as it is? What do these things run at if you dont specify a frequency?
I've also noticed that the speed fluctuates regularly, although it's averaging at around 1.363gh/s, watching the (5s) in the top left hand corner, it drops down to 600-800 mh/s then up to over 2 gh/s, should this remain relatively static or is it normal for it to fluctuate like this?
Don't worry about the 5 second rate, it's the long term rate that matters most.
It is safe to experiment with the speeds so long as you have some cooling. Try from the lowest speed first, then build up and see what happens.
Give each setting plenty of time to stabilize before trying the next one. If you go above 2Gh you will probably need a powered hub to supply the extra current.