I have P180 with Asus P5B. When I put an extra fan in the upper hard-drive cage, it reduces my SB temp by about 6 C. However I cannot mount any hard-drive in that cage anymore.
Yeah i had that problem but if your gfx card is 10.5" just remove the lower hard drive bay and mount a fan inside the case. That 120mm fan will suck cold air from out side and blow it directly into the gfx intake as well as blowing cold air directly over the southbridge. You should go to the bios and set the Southbridge voltage to the lowest voltage setting available. Also if your northbridge voltage is set to auto, it will be unnecessarily high. You can achieve stability at 1.2V @ 4ghz with the x58. I'm sure you could go lower say 1.875V might be the sweet spot for 4ghz on the northbridge.
As for the upper hard drive bay, Install the hard drive bay up top. Remove the upper flip open white door and filter. First thing you will want to do is find the metal hole that is just the right size to squeeze your 3-pin power connector through, pull it all the way through. Now zip tie the top left and bottom right fan holes into the fan holes. At this point you will have superior cooling for the northbridge and southbridge. Antec made some serious designs flaws on this case that drive me crazy! otherwise it's the best cooling microatx case for Core i7 X58 systems. Antec should have made the case longer so u can install a 10.5" graphics card and still keep the hard drive cage in there. Also they should have designed it correctly as to be able to mount fans both on the top and bottom of the front of the case with the cages installed. Anyway i scrapped the case because i couldn't install enough hard drives, now everything in my system is running way hotter! I'm going to custom build a case using a $20 rosewill case on newegg, custom mount a hard drive cage that will hold 6 hard drives and engineer it to fit the 10.5" graphics card with sufficient cooling that should/ will exceed the antec p180's cooling design. Good Luck!!!