(SSD)Slower booting and shutdown because of Windows Update?

I was so happy when I got my ADATA SX900 because after installing windows 7 in it the booting was instant, under 10 sec and shutdown was 3 sec. After windows update i notice that my shutdown is taking long I timed it (36s) and  my booting increased to 16s. Is it better to not use windows update ? Since i have my own Antivirus and my drivers are always updated. Any opinion if Its better just to turn off windows update and never update windows.