In terms of overall gaming performance, the Intel Core i3-530 2.9GHz is noticeably better than the Intel Pentium J2850 2.4GHz when it comes to running the latest games. This also means it will be less likely to bottleneck more powerful GPUs, allowing them to achieve more of their gaming performance potential.
The Pentium J2850 2.4GHz was released over three years more recently than the Core i3-530 2.9GHz, and so the Pentium J2850 2.4GHz is likely to have far better levels of support, and will be much more optimized and ultimately superior to the Core i3-530 2.9GHz when running the latest games.
The Pentium J2850 2.4GHz has 2 more cores than the Core i3-530 2.9GHz. With 4 cores, the Pentium J2850 2.4GHz is much less likely to struggle with the latest games, or bottleneck high-end graphics cards when running them.
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 Pentium J2850 2.4GHz and Core i3-530 2.9GHz are not from the same family of CPUs, so their clock speeds are by no means directly comparable. Bear in mind, then, that while the Core i3-530 2.9GHz has a 0.53 GHz faster frequency, this is not always an indicator that it will be superior in performance, despite frequency being crucial when trying to avoid GPU bottlenecking. In this case, however, the difference is enough that it possibly indicates the superiority of the Pentium J2850 2.4GHz.
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 Pentium J2850 2.4GHz has a 1536 KB bigger L2 cache than the Core i3-530 2.9GHz, and although the Pentium J2850 2.4GHz does not appear to have an L3 cache, its larger L2 cache means that it wins out in this area.
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.
The Pentium J2850 2.4GHz has a 63 Watt lower Maximum TDP than the Core i3-530 2.9GHz, and was created with a 10 nm smaller manufacturing technology. What this means is the Pentium J2850 2.4GHz will consume significantly less power and consequently produce less heat, enabling more prolonged computational tasks with fewer adverse effects. This will lower your yearly electricity bill significantly, as well as prevent you from having to invest in extra cooling mechanisms (unless you overclock).