Windows 7: Not showing exact graphics memory

Hi all today now im in trouble having a proper graphics memory. My problem is when i select gpu id software it shows everything normal and it shows you have ati radeon 5770 and shows u have 1gb but when i check my system online with srtest.com or even i open dxdiag through the windows run panel in the display settings i got approx 701mb memory of gpu memory. I don't what is that and also my windows experience score down a little bit. I hv already done a clean installation of windows 7 ultimate but nothing happen. and also i have 8gb ram ddr3

It's a bug and happens to both AMD and Nvidia cards,

How to Troubleshoot? ATI Radeon HD 5770 (Dual Cards)

The WEI I wouldn't worry about as that can change from one driver to the next. It can also change from one day to the next depending on what else may be running when you run the WEI. As long as games aren't affected then I wouldn't worry about it too much.