In terms of overall gaming performance, the Intel Core i5-9400F 6-Core 2.9GHz is massively better than the AMD Opteron 4230 HE 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 Core i5-9400F 6-Core was released over three years more recently than the Opteron 4230 HE, and so the Core i5-9400F 6-Core is likely to have far better levels of support, and will be much more optimized and ultimately superior to the Opteron 4230 HE when running the latest games.

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 Core i5-9400F 6-Core and the Opteron 4230 HE both have 6 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 Core i5-9400F 6-Core and Opteron 4230 HE 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 i5-9400F 6-Core and the Opteron 4230 HE both have the same clock frequency, this is by no means an indicator that the two CPUs will provide the same level of performance. As such, we need to look elsewhere for more reliable comparisons.

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 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 Core i5-9400F 6-Core and the Opteron 4230 HE have the same TDP of 65 Watts, but the Core i5-9400F 6-Core has a lower lithography size, and so will affect your yearly electricity bills less adversely.