kiniu wrote on Dec 13^th, 2010 at 10:41pm:

hello I did one test 2 years ago I install fsx without any addons and I try to play on high setting and this was working just  fine about 30 fps all the times I think is enough. when we start install new airport and aircraft FPS drop down drastically and we need to minimize the setting to play the game. Today I buy new video card nvidia geforce 480 gtx just to play fsx with high setting and frame rate better  then 8 fps on Egll mega airport heathrow. Unfortunately my power supply is to weak to give enough power my graphic card so tomorrow I will need to buy 850 watt monster

You are on the right track for sure, this is a link to a different thread offering a fix for this same exact issue...

http://www.captainsim.org/yabb2/YaBB.pl?num=1291943175

Also a good power supply calculator from newegg and easy to use.

http://c1.neweggimages.com/BizIntell/tool/psucalc/index.html?cm_sp=Cat32_PowerSupply_left-_-PowerSupplyFinder030510-_-http%3a%2f%2fpromotions.newegg.com%2fproductfinders%2fpowersupply.jpg

PC's are far under powered and a good solution to many problems is providing the right power source to your PC,My ATI is 500W minimum and my PC came with 475W! The i7 uses around 250W! Do the math, that doesn't include the monitor or anything else I have, you will be upset at how much you've missed by not doing it sooner.
Good Luck 8-)

i7 CPU  920  @ 2.67GHz, 2668 Mhz,
RAM9.00 GB DDR3 1600
ATI HD 5870