In terms of overall gaming performance, the i5-3570K 3.4GHz and the i5-3570K 3.4GHz are equal when it comes to running the latest games. This means they will be about the same in terms of bottlenecking (or not bottlenecking) GPUs.
Both the Core i5-3570K 3.4GHz and the Core i5-3570K 3.4GHz were released at the same time, so are likely to be quite similar.
Both CPUs exhibit very powerful performance, so it probably isn't worth upgrading from one to the other, as both are capable of running even the most demanding games at the highest settings (assuming they are accompanied by equivalently powerful GPUs).
The i5-3570K 3.4GHz and the i5-3570K 3.4GHz both have 4 cores, which is not likely to be a limiting factor for gaming.
More important for gaming than the number of cores and threads is the clock rate. Problematically, unless the two CPUs are from the same family, this can only serve as a general guide and nothing like an exact comparison, because the clock cycles per instruction (CPI) will vary so much.
The i5-3570K 3.4GHz and the i5-3570K 3.4GHz are from the same family of CPUs, and thus their clock speeds are directly comparable. That isn't particularly helpful, however, as the i5-3570K 3.4GHz and the i5-3570K 3.4GHz provide identical clock rates and thus extremely similar performance.
Aside from the clock rate, the next-most important CPU features for PC game performance are L2 and L3 cache size. Faster than RAM, the more cache available, the more data that can be stored for lightning-fast retrieval. L1 Cache is not usually an issue anymore for gaming, with most high-end CPUs eking out about the same L1 performance, and L2 is more important than L3 - but L3 is still important if you want to reach the highest levels of performance. Bear in mind that although it is better to have a larger cache, the larger it is, the higher the latency, so a balance has to be struck.
The i5-3570K 3.4GHz and the i5-3570K 3.4GHz have the same L2 cache size, and the same L3 cache size, so in terms of cache-related gaming performance, the two CPUs are practically identical.
The maximum Thermal Design Power is the power in Watts that the CPU will consume in the worst case scenario. The lithography is the semiconductor manufacturing technology being used to create the CPU - the smaller this is, the more transistors that can be fit into the CPU, and the closer the connections. For both the lithography and the TDP, it is the lower the better, because a lower number means a lower amount of power is necessary to run the CPU, and consequently a lower amount of heat is produced.
Both the i5-3570K 3.4GHz and the i5-3570K 3.4GHz have the same TDP of 77 Watts, and were created with the same manufacturing size of 22 nm, which means they will affect your yearly electricity bill about equally.
The i5-3570K 3.4GHz and the i5-3570K 3.4GHz both have an on-board GPU, which means that they will be capable of running basic graphics applications (i.e., games) without the need for a dedicated graphics card.
For an in-depth GPU comparison, click on the GPU comparison icon that you can find throughout Game-Debate:
On-board GPUs tend to be fairly awful in comparison to dedicated cards from the likes of AMD or Nvidia, but as they are built into the CPU, they also tend to be cheaper and require far less power to run (this makes them a good choice for laptops). We would recommend a dedicated card for running the latest games, but integrated GPUs are improving all the time and casual gamers may find less recent games perform perfectly acceptably.