Shuttering game while having 60+fps and high ping

Heya, since about 4-5 days ago the game started to shutter, in big fight like a 8v8, it even starts to shutter unplayable when there's allot of action. My fps remains 70+ though and my ping is arround 20.
Computer Specs:
Intel i5 cpu
Ati 5850 gpu
4gb ddr3 ram
700W power supply
playing on a 1920x1080 screen changing resolution to 1024x768