Looking to buy 2560x1440 monitor

[Methodius]

K so i want to buy 2560 × 1440 ips monitor will my rig be good enough?

CPU: 2500K (i will overclock it)
MB: Z77A-GD65
RAM: 4GB (i will buy more for sure its cheap)
GPU: Crossfire msi 7850 2GB twinfrozer (currently one bud another is on the way i hope iu will be able to get stable 1200 mhz overclcok from second one so i can run them oced in crossfire)
PSU: corsair 850W

problem is that im not sure that i can get stable 100 plus HZ in that resolution i have made a mistake when i bought first card because i didnt know back then that there is option for 120hz IPS i thought i will buy same 120hz 1920x1080 TN monitor, another problem is that i have sandy bridge which means that i can only utilise 2 x 8 pcie 2 and not pcie 3 so i will have limited brandwich for such resolution

SO what do u guys think?

Ps: sry for engrish