Yes that's fine.
The CM 460W should be enough for HD 6770 power requirements which is only 110W.
Happy Gaming. Though I would prefer a HD7790. Thanks
Is there any performance drop if I use 7770 in pcie 2.0 x16?
There will be no noticeable performance loss using a PCIE 3.0 card in a PCIE2.0 Slot. These cards are PCIE backward compatible. Thanks