How many times are you going to do this? Its pretty obvious hes on a tight budget (If I'm wrong then I apologise, Intel would be the option for performance), yet here you are again telling someone to spend £250+ because the tech is outdated blah blah. The performs horridly in comparison to the i5 comment is not completely true now is it. If he could afford it, we would recommend it, but he already has a AMD CPU and £75 would get him a pretty good mb for it. He also has admitting to being quite new to all this. Do you not think a leap to intel is not a little daunting especially considering he would have to re-install windows, of which he doesnt have a hard copy of, mentioned earlier (have you even bothered following the thread?). Are you going to talk him through the process of re-installing and new intel configuration which he has even less experience of? If you are, hat off to you.
Anyway, sorry for the rant, I'm just tired of the same old from Dave without him giving a thought as to why AMD is a valid option for budget orientated buyers. If you are not one of these, then yes Dave is right, you will get a more consistent performance boost going I5.
As for new motherboard, it would certainly be better than your current one, but as said before, you dont want to be buying anything, only to be faced with the same issues. However I can make these recommendations for a cheapish mb that can easily handle your FX.
http://www.overclockers.co.uk/showproduct.php?prodid=MB-471-GI&groupid=701&catid=1903&subcat=2046
or
http://www.overclockers.co.uk/showproduct.php?prodid=MB-502-AS&groupid=701&catid=1903&subcat=2046
Both good boards. Limitation of the 970s chipset (compared to the higher prices 990s) is just the PCIE config that should only affect you if you go xfire/sli (dual card one will be x16 and ther other x4). If you only plan to stay with 1 card, its nothing to worry about.
However before going ahead with spending, try and corner Davedree a bit more, he's pretty good with getting these chip running on lower boards.
I don't have much else to offer at this point.
Did you try the bump up in voltage? Results?