I purchased a P4 670, Sspec SL7Z3, running @ 3.8 GHz, L2 cache of 2MB. I had already upgraded to the A10 BIOS a while back so when I put the 670 in, reapplying Thermal paste to both processor and heatsink, my 4700 fired right up and has not given any problems. I had also reversed the fan last year and that cooled the case temp down alot.
Conflicting info there, but I suppose it's worth a shot, if the 670 won't cost you much. It's not like it'll be a night and day difference or very worthwhile upgrade anyway, though.