That's a high oc for the base 3.4GHz which would have put the voltage up and increased the temperatures a lot. I'm not surprised to see a closed-loop system cooling the processor but the h100i isn't that great for cooling.
You need to be aware that before you start an oc, you need to know a couple of things. There is a chance that your processor just won't handle the oc or you won't get the desired oc results that you're hoping for. There is no guaranteed oc so bare that in mind. You will also need to compensate for the increased voltage on the processor which will in turn require a larger power supply and the temperatures on the processor will increase. You will also need a solid motherboard that can handle the oc.
The ud3 is good for oc'ing, so is the fx990 as two examples. You're going to need a good board, decent cooling and a lucky break that your processor will push its limits before hitting a thermal wall or throttling with temperatures.
The 8320 or the 4440 are fine for gaming. Games utilize dual cores and only some games like BF4 are utilizing quad cores. The 4440 cannot be overclocked because it is locked. The 8320 can obviously be oc'ed so that's a point to the 8320. Single performance the 4440 will run slightly better because of the architecture for the cores and the instructions per cycle. The 4440 has a built in chipset so you don't need to rush out and get a graphics card instantly and with a lower power consumption, the processor won't be drawing as much heat as the 8320. The 8320 has the higher clock speed and turbo clock than the 4440 and is obviously hyperthreaded.
The 4670k will be dominant against both the 4440 and the 8320, can be overclocked because it isn't locked and has very similar clock speeds at base clock and through turbo boost (air).
The 280x and 270x are just rebranded 7870/7970s with a higher overclock, pcb and heatsink upgrade. Expect 40-45 fps on high with the 280 and a 4670k.
The average price of the 8320 is roughly £100-£100, on top of that you need a decent board if you plan to oc and a after market cooler. The 4670k is roughly £150-£160 and you already have almost the same clock speed against the 8320 and (imo) the architecture on the Intel cores are vastly superior because clock for clock, Bulldozer won't touch Haswell. Amd counters this by boasting about their HSA and Mantle which will take years before most applications are using it but when they do, AMD's chips will certainly make an impact but will it do anything special?
Broadwell is coming around the corner and the Haswell 1150 socket might not be compatible with Broadwell but nobody knows. AM3+ won't be supported for that much longer so you might want to think about future proofing as much as you can so you save money in the long run as well.
http://www.hardocp.com/article/2013/11/17/battlefield_4_video_card_performance_iq_review/5#.U-KbWfldX5N