EasyLover :
This may happen due to native power saving profile of PCI express. If you happen to have a GPU-Z. Run that program, you'll find a icon next to PCI Bus Interface on the main page. Click that icon. It will open a small window in which click at run test button. One the test is started, check the PCI Express Bus Interface, It should report 3.0.
GPU-Z reports the bus interface is PIC-E 2.0x16 @x16 1.1 when video card is at idle
When I run a video card benchmark or the rendered test it changes to PIC-E 2.0x16 @x16 2.0
here are the specs for my computer
Gigabyte GA-Z77X-UD5H
Intel Core i7-3770K
Microsoft Windows 7 Professional 64
EVGA SuperClocked GeForce GTX 780
EVGA SuperNOVA 1000 G2
Crucial Ballistix Tactical Tracer 16GB Desktop Memory
Crucial M4 128GB SATA III MLC Internal Solid State Drive 2x in raid
Western Digital 250GB 5400 RPM 8MB Cache SATA 3.0 2x in raid
Antec KUHLER H2O 920 Liquid Cooling System
ASUS VE258Q Black 25" 2ms HDMI LED LCD Monitor
so now I'm more confused why my card is running at @ PCI-E X 16 2.0
and idling @ PCI-E X 16 1 .1