So now you know how to find out which processors are compatible with your system after reading my General CPU Compatibility Guide, but which one is the right one for your usage? Which option will give you the best value and what will work the fastest for you? Which one is going to turn your computer into a space heater and what is going to save you money on your energy bill? There are lots of things to consider when choosing a processor and in many cases, it isn't as simple as buying the most expensive one you can afford. I will guide you through this consideration process and help you make a smart decision
Some people will disagree with this, but I think the first thing to consider about your budget is that it is largely irrelevant. Don't come in with the mindset that you have $300 to spend. Instead, evaluate the task you are doing and try to get the processor that will do the best job for you for the least amount of money. What I mean by this is that if you are just doing standard office tasks like web browsing, excel or word then there is very little to gain from having a $300 dollar processor. You would have your needs met all the same for under $100. On the flipside, a $1000 processor may seem absurd to some. That is more than many people's computers cost now. But if you are someone doing hard rendering work or video encoding or some other intensive task and buying a $1000 processor instead of a $300 processor is going to save you 30 minutes a day and you value your working time at $25 an hour, you will earn that value back in less than a quarter of the year. This is why I tell most people who have a number in their head to throw it out the window. Adhering to an arbitrary budget will likely make you spend too much or too little. The important thing is to get your need met in the most efficient way possible.
In my opinion evaluating your usage is the most important thing to look at when deciding which processor to buy. What I mean by usage is very simply just what you do throughout the day or what you plan to do throughout the day on this computer. Is it a box just for streaming video? Is it a video editing station? Is it a 4k video game rig? Does it need to host piles of virtual machines? Whatever it is doing, consider the software that will be run. Is it something that functions in a good-enough fashion? It either does the job correctly or doesn't. Or is it a speed-benefitting task? Would a faster processor save you time or give you better performance in the task? If, for example, you are playing video games, after a certain point there is no benefit to a faster processor. You have already reached an acceptable frames per second and the game will be enjoyable at the resolution you are using. But if your game is just on the cusp of being playable it may be very worth it to go for the higher clocked processor.
So now you have considered what the machine will be used for and determined whether you really need speed or just something that is able to run things correctly. The next thing to consider is are the programs you use properly multithreaded. Multithreading is when a program uses more than one core of the processor. For a long time, games were only using two or in sometimes four cores, but we are slowly moving beyond that. No matter what your task, it is valuable to look around the forums for that software and try to find out if it would even use the extra cores if you are deciding between two different core count options. Keep in mind that your machine will be able to do other concurrent tasks better if you have more cores, but you may not get any benefit from some of the apps you are using simply because you have more cores. If the biggest thing you are worried about is encoding a video using some software and you see that that software doesn't seem to get a proportional gain to the increased core count then it may be better to look at a different option or just go for the lower core count model.
One of the most common determiner's of speed in days old was GHz. This used to be a pure metric on how fast the processor would be, but now we have so many different models and architectures and manufacturing nodes that you can't simply say that a 3.2GHz chip beats a 2.8GHz chip. Instead, now, a user must simply look at benchmarks and see how an individual processor performs a task because the GHz number does not mean a whole lot. If a processor is of the same generation and the same series and has the same amount of cache (this is basically really fast on-processor RAM) then you may look at GHz as an indicator, but for the beyond that it is really best to simply view benchmarks. Anandtech and Tomshardware are great places to start with these. Processors these days simply have too high of a range of IPCs(Instructions per cycle, basically how fast a processor is in reference to it's GHz). That being said, there is still plenty of room to optimize purely on GHz. Like I said previously, a software may not benefit from increased core count, but it likely does benefit from an increased clock speed. In certain tasks, like gaming, that is why a $300 6700k with 4 cores will almost always outperform the much more expensive 10 core $1700 6950X. The games cannot efficiently take advantage of the additional threads, but they can take advantage of the higher clock speed.
TDP (Thermal Design Power)
TDP or thermal design power is, for our purposes, at least, the amount of power that the processor uses and heat it puts out. This something else to consider when picking your processor. This number has slowly crept down over the years as manufacturers have made more efficient processors, but it is still not insignificant. If you are in a small enclosed room you can definitely increase the ambient temperature by a few degrees if you have a high wattage processor and you run it for full tilt for a while. In many places, the electricity cost is negligible even across an entire year of usage, but it does add up in places with high electricity costs. If you want to see a quick estimate of what a difference between two different wattages of processors will cost you can visit this site and enter in the different wattages of the processors you are considering and your electricity cost and your estimated usage. One other thing to consider is that if you are going to run the AC to counteract the increased temperatures in your room you will actually be paying double for the increased wattage. If this is something you are concerned about then you might want to consider a processor that ends with "T" in the model name. These are Intel's low wattage variants and they have some chips there that perform just as well as their higher wattage siblings.
Overall, what I want you to take from this article is that there are a lot of things to look at with processors, but ultimately it comes down to meeting your needs in the most efficient way possible. Don't come into this process with a set number in mind and instead try to find the correct tool for the job. Figure out what the expected usage is and whether or not the applications you use would benefit from more cores or if they really need higher clock speeds or higher IPC. Then consider if you are in an environment where TDP is important to you or if there is a variant that will save you money on electricity and AC costs while still meeting your needs. If you follow this framework you will likely find you can make a better decision.