Interesting. I have the original Biostar Tforce TA790GX which I run a X4 940 with 1066Mhz OCZ Reaper and haven't had any troubles running at any speeds. I currently run them at ~1100 ref clock 205 5-5-5-15 timings with a processor speed of 3.7Ghz.
I guess the gxb could have some differences, my mobo was kinda the reference design, no sideport. I don't know about the gxb board but I noticed right away what the reviews on the egg were talking about when discussing the quite high temps on the chipset. I ordered a chipset cooler and it runs at ambient now, have had no problems with this board whatsoever in the last year.
I got this board to replace a $240 ASUS Crosshair that gave me no end of trouble. This board has been like a dream. $100 well spent. I have had good luck with Biostar.
does the Biostar TA790GBX allow you to change the CPU clock multiplier?
I have a A740G running a Phenom 9950 BE 140watt. this board isn't supposed to run cpus above 95 watts but it's run great for almost a year, just wanted a cheap upgrade with the ability change the mulitplier.