I would definitely recommend upgrading from the 1055t, especially where gaming is involved. I recently swapped my 1055t @ 3.8GHz for a 3930K, and I must say it makes a massive difference in gaming. Considering I was using a GTX 670 before and after the upgrade I can clearly see a massive increase in FPS. For example World of Tanks used to get about 20-30 fps with the 1055t, partly due to the single core optimisation of the game, but now I get a steady 60fps with v-sync enabled.
Granted the 3930K is a pretty big upgrade from the basic six core phenom model, however I think you would see the same performance in gaming with a 3570K. I also didn't point out that my 3930K is clocked @ 4.6GHz, which probably has quite a big bearing on single threaded performance.
At the end of the day if you current motherboard can support the Piledrivers, it may be worth looking into the 8350 as it is supposed to be on par with the i5 in terms of many applications, especially with a large overclock.