In terms of overall gaming performance, the Intel Core 2 Quad Q8200 2.33GHz is noticeably better than the Intel Core 2 Duo E8500 3.16GHz 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 2 Quad was released less than a year after the Core 2 Duo, and so they are likely to have similar levels of support, and similarly optimized performance when running the latest games.

The Core 2 Quad has 2 more cores than the Core 2 Duo. With 4 cores, the Core 2 Quad is much less likely to struggle with the latest games, or bottleneck high-end graphics cards when running them.

The Core 2 Quad has 2 more threads than the Core 2 Duo. Both CPUs have one thread per physical core.

Multiple threads are useful for improving the performance of multi-threaded applications. Additional cores and their accompanying thread will always be beneficial for multi-threaded applications. Hyperthreading will be beneficial for applications optimized for it, but it may slow others down. For games, the number of threads is largely irrelevant, as long as you have at least 2 cores (preferably 4), and hyperthreading can sometimes even hit performance.

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 2 Quad and Core 2 Duo 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 2 Duo has a 0.83 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 probably a good indicator that the Core 2 Quad is superior.

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 Core 2 Duo has a 2048 KB bigger L2 cache than the Core 2 Quad, but neither of the CPUs have L3 caches, so the Core 2 Duo wins out in this area with its larger L2 cache.

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 Core 2 Duo has a 30 Watt lower Maximum TDP than the Core 2 Quad (though they were created with the same size 45 nm manufacturing technology). What this means is the Core 2 Duo 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).