Since Blu-ray renders tax primarily the CPU, a GPU upgrade would not likely help you much at all.
What is the rest of your system now? (CPU, RAM, which version of Adobe, drives, etc.)
GPU does work i mainly deliver my projects BD disk along with DVD, In rendering 1080 seq to 576 MPEG-2 DVD my GTX 580 is like on 70 to 80%. I think its helping in down scaling but i think on rest of my work like photoshop or editing it doesn't help alot i mean looks over kill to me. so should i get 650 ti boost?
i7 4770 (Thermaltake SpinQT cooler)
16Gb Corsair Vengeance 1600 (8GBx2)
EVGA Gtx 580 1.5 Gb
256 Crucial SSD (c drive)
256 Crucial SSD (for exports)
2Tb WD Black (Projects AVCHD files etc)
1Tb WD Black (Media)
2Tb WD Green (Backup)
Corsair 950TX PSU
CoolerMaster HAF 932 Chassis
Rather than replacing the video card, consider upping the memory to 32 GB.