I made a third MOD i take the old PSU doughter card that has the thermal diodes for temps in psu1 and psu2 fixed to 45c so mac think the psu is at 45ºc and the fans goes to normal speed, the PSU pwer OK conected to gray cable on ATX power PSU goes high +5v ... i then use a sigle corsair 1000w PSU ... it worked well for 6 month... then started again random reboots.... THE PROBLEM IS FAULTY MOTHERBORAD THERE ARE SO MANY PEOPLES REPORTING THIS PROBLEM AND APPLE IS IN SILENCE.... I tried every thing remove1CPU (b) and the problem persist, chage CPU (a) to (b) the same, with fans at 2000 rpm very cold working the problem persist, i monitored temps and voltages and amps in every test i made 12v go to 12,3 in idle and 11,9 ful load running cinebench, memtest, itunes movie simultaneos... for more then 3 hours no problem but then after 3 mores hours it startedd ramdom reboots... i changed video cards hd 2600 stock, a hd 5770 with external 6 pin cable, nvidia gt640 pc card... it booted but after 3 to 6 hours ramdon reboots again, i tried with 2 gb stock memory, with 4gb avant modules, with 8 gb nemix ram, with all togeder and the thing ramdom reboots, i try remove 1 raiser card no diference inter change raisers cards, clean al contacts same issue i dedicated 1 hours to this thing mesurements... i replaced all capacitors in the mother board... same thing... worked well 1 month then ramdon reboot... what i see is corrosion in the motherboard ... i make my power cables to the motherboard awg 16 for every conector, i also make shorter cable to the bottom conector to improve power loss ... it continues the ramdom reboot i finaly take all apart and put it in the garbage can... APPLE KNOWS THAT ALL OR A LOT OF MAC PRO EARLY 2008 HAVE THE SAME PROBLEM AND THEY DONT SAY NOTHING... AFTER WEE SPEND $3000 ON THIS THING ... Same thing goes with the imac 2008 VIDEO CARD... Lot of people having same problem, same goes with mac book pro 2008 video problem... APPLE MACHINES FROM 2008 TO 2010 HAVE MANY PROBLEMS... And all that problems begins 1 year later when your garanty is lost... there are so many bad reports on 2008 mac pro having the same problem the $3000 lotery