Which processor do I buy ?????

AMD is a different company and different technology (WORSE technology) than Intel. AMD used to be great back in the days because they performed the same if not even better than Intel and was also alot cheaper. Now they are still cheaper but alot worse when it comes to performance :/ If it's an office computer with occacional gaming just get a Core 2 Duo computer. Dual Core is 1st gen so it's a bit old. Essentially the same just newer technology for the Core 2 Duo. Good luck :)

What we need to know what will the PC be used for? If you'll be doing some advanced calculations, encoding video or you are a hardcore gamer who has unlimited amount of money I would suggest you one of the Intel i7 CPUs. If you want to pay less, but still you want to have powerful PC I suggest you one of the AMD Phenom II (not first generation) CPUs. Dual Core are old CPUs with two cores, Core2Duo is newer version of the Dual Core CPU. The main differences between AMD and Intel CPUs are the price (Intel is more expensive), slots (you can't put Intel on AMD motherboard) and some will say performance. Intel maybe is slightly better than AMD in everyday work, but if you benchmark you'll see that seems to be much worse than Intel; the truth is different, CPU isn't meant to do benchmarks, so don't take those benchmark result seriously. In some cases benchmark will show where the CPU stands, but it doesn't mean it has bad performance or something. Happy mylotting! I would go for the AMD, but I'm the Intel hater and AMD fan...