So I've seen a lot of "build guides" where the OP just creates a bunch of builds and doesn't explain why he does what he does (mine included), so I'm going to try to explain the basics of HOW to specifically choose your components. Let's begin:
CPU
When choosing a CPU the most common mistake is to pay attention to cores and speed. Some others also look at the amount of L3 cache, and call it a day. The truth is there are other things to look out for, such as architecture and manufacturing technology. I'll explain them all the best I can:
- Architecture: There is no good way to measure how different architectures impact performance. As a general rule, newer architecture = more performance. Keep in mind, Intel and AMD have different architectures. The latest architectures at the moment are Kaby Lake (Intel), and Ryzen (AMD). Therefore it is recommended to build using this ones, since it will help future-proofing your build. In case your CPU is a bit behind, you can trade it with it's superior models, without changing motherboards. The best CPUs from each architecture generally stay relatively powerful as times go by. So, let's say I bought a Pentium G4560, and few years from now, it's not good enough. So instead of changing my entire rig, and buying the newest Pentium with the latest architecture, I just buy an I7 7700 and will still be decent, and probably better than the newest Pentiums. Exactly the way it happens today. Within the same architecture it is ok to compare the other specs. If I have 2 Kaby lake CPUs and one has 2 cores and the other has 4, then chances are the 4-core Kaby is better than the 2-core Kaby.
- Manufacturing technology: It usually only affects the TDP of your CPU, which basically determines how much heat your CPU will produce. Examples are 32nm, 14nm, etc.
- L3 Cache: Has an impact depending on how CPU bound the game or software is.
- Cores: Pretty self explainatory. The number of physical cores the CPU has. Doesn't really matter unless you are comparing CPUs within the same architecture.
- Threads: Usually each core is able to handle 1 threat. However, with Intel's Hyperthreading and AMD's SMT, some CPUs can handle 2 threads per physical core. That in some cases, translates into better multithreading. Some other times in better performance, because of the way CPUs handle their cycles more efficiently.
- Speed: The same as cores. Can't be interpreted as the real-world performance the CPU has. There are many 3GHz CPUs better than 4+GHz CPUs. It really doesn't tell you much unless you are comparing within the same architecture.
Motherboard
The motherboard itself won't affect performance directly. Getting a better motherboard will not translate into, let's say, better FPS in a game. It can, however, limit the components you use, and the amount of overclocking you can achieve.
- Socket: This is the most important thing when choosing motherboards. You MUST make sure it has the socket to which your CPU belongs. If your CPU is a Kaby, you'll need a 1151 socket motherboard. This doesn't affect funcionality directly, but it has to match your CPU. Otherwise the CPU won't fit, and you'll have a problem.
- Chipset: Usually chipsets limit what a motherboard can do, or how a motherboard is designed. Some chipsets allow overclocking, others do not. Some allow Crossfire, others do not, and others handle it differently (such as the X370 and B350 motherboards from AMD).
- VRM: The voltage regulator module is a very important part of the Motherboard if you are interested in overclocking. I've seen very few guides actually addressing this. They usually take the form of numbers, like "12+2", or "4+1". Some CPUs require a high phase count for a decent OC (like the FX lineup from AMD, because of their high TDP, and some others do not). The VRM affects the way current is delivered to the CPU, splitting the load between the phases. The more phases, the cooler they run, the more overclock you get without experiencing instability (Blue screens and/or stuttering).
- Crossfire/SLI support: What it says. Whether if it supports SLI or Crossfire, and sometimes the way it does it. The best example are the AM4 boards (the X370 boards use 8 lanes for each card on Crossfire, whereas the B350 use 16 and 4).
- Supported RAM: The amount and speed varies from one motherboard to another. Generally they are so high you won't have to worry about it (usually 64/128Gb and 3000MHz+).
RAM
This is where your PC keeps the files you are using at the moment. If your PC runs out of RAM, it will use free HD space to store them, and your HDD (even SSD) is exponentially slower than the RAM, and will result in heavy performance losses.
- Interface: Can be DDR4, DDR3, DDR2, DDR, etc. DDR2 and DDR already are very outdated. DDR3 is still decent. All new boards use DDR4.
- Speed: Measured in MHz. For example 2400MHz. This, however, is not the real speed. The real speed is half of the labeled speed. In the 2400MHz situation, the real speed will be 1200MHz. RAM is usually advertised as DDRxxx/PCayyyy. Example DDR3-2400/PC3-12800. That means it has a frequency of 2400MHz and the max data transfer is 12800 MB/s, and it's DDR4.
- Size: Depends of what you are using the PC for. If you are gaming, 16Gb for now is perfect. For other uses, depending on how intensive, you may require more.
- Dual Channel: Technology that allows for the speed to be doubled when using different RAM channels in the motherboard. Requires at least 2 RAM sticks.
- Mixing different RAM sticks: ALWAYS make sure your RAM uses the same interface supported by the motherboard (you can't mix DDR2 with DDR3), also sticks MUST have the same timings and recommended voltages, or you'll have to spend some time manually tweaking them. If you get something with different speeds, your motherboard will automatically downclock the faster stick to match the slower one.
Storage
Basically when choosing storage, the standars is to get: 1 SSD and 1 HDD. All you need to know is SSDs are faster (faster read and write speeds), but a lot more expensive (a 250Gb SSD costs from $80 to $150 or more) and HDDs are slower, but their price/Gb ratio is much better (1Tb HDDs can be as low as $50). Couple of thngs you have to know about both:
- Interface: Both SSDs and HDDs use SATA (SSDs also use M.2). You have to make sure your HDD is SATA 6Gb/s and not something else. Older drives have SATA 3Gb/s, SATA 1.5Gb/s, etc. This does not mean they have 1.5Gb/s write and read speeds, but rather 1.5Gbit/s, which translates into 150Mb/s (1Gbit =~ 119Mb).
- Rotation speed: Measured in RPM, it basically tells you how fast is your HDD. The standard is 7200RPM. This does not apply to SSDs since they do not have any moving parts.
- Cache: Not too important. If you can, get something with 64Mb, otherwise 32Mb will be all right. Theoretically will help you load programs faster.
GPU
This one is rather simple. It all comes down to how much money you put into it. Some have a better price/performance ratio, but essentially that's how it works. The same as CPUs, you can't use specs alone to compare cards with different architectures. Some of the specs are Core speed, Memory clock, CUDA cores, amount of VRAM, etc. The only one that could be a limiting factor is VRAM. The higher your resolutionm, the more VRAM you need. For now 4-6Gb should be allright for up to 4K resolutions when gaming. The best way to compare cards is by using Benchmarks (userbenchmark.com being my favourite). Just to be clear I'll explain what VRAM does.
- VRAM: It's the memory of your GPU, where the card stores the textures rendered. If you run out, it will start using your system's regular RAM, which is exponentially slower and you'll loose a great deal of FPS. Having enough VRAM is incredibly important (if you run out of RAM too, you'll start using disk space, and that's way slower).
PSU
The PSU is a very important component, often neglected. The biggest problem with PSUs is the lack of information provided by the designers, and the deceitfullness of the 80plus certifications, which ARE NOT A MEASURE OF QUALITY. There is only two ways to know if a PSU is good: You open it up, and check it yourself, or, you can leave it to the pros. JonnyGURU.com is an amazing site with plenty of reviews, and he is a firm oppositor of the so called "PSU tier lists". So am I. The problem with this lists is the lack of context. Now to understand his reviews there are some things you gotta keep in mind.
- Date: If a PSU got a good final score, but when you look at the date it's 7-10 years old, chances are the unit is not as good anymore.
- Read everything: Don't just stick to the "recommended" units. Define a budget, find what decent PSUs are there (generally by looking at the most popular brands, like Corsair, EVGA, etc.), and then investigate each model.
That would be the end. For the case just pick something you like and that fits everything you need (DO NOT get a case w/PSU, they are usually terrible). Next I'll leave a link to some gaming and productivity builds.
Build guide
CPU
When choosing a CPU the most common mistake is to pay attention to cores and speed. Some others also look at the amount of L3 cache, and call it a day. The truth is there are other things to look out for, such as architecture and manufacturing technology. I'll explain them all the best I can:
- Architecture: There is no good way to measure how different architectures impact performance. As a general rule, newer architecture = more performance. Keep in mind, Intel and AMD have different architectures. The latest architectures at the moment are Kaby Lake (Intel), and Ryzen (AMD). Therefore it is recommended to build using this ones, since it will help future-proofing your build. In case your CPU is a bit behind, you can trade it with it's superior models, without changing motherboards. The best CPUs from each architecture generally stay relatively powerful as times go by. So, let's say I bought a Pentium G4560, and few years from now, it's not good enough. So instead of changing my entire rig, and buying the newest Pentium with the latest architecture, I just buy an I7 7700 and will still be decent, and probably better than the newest Pentiums. Exactly the way it happens today. Within the same architecture it is ok to compare the other specs. If I have 2 Kaby lake CPUs and one has 2 cores and the other has 4, then chances are the 4-core Kaby is better than the 2-core Kaby.
- Manufacturing technology: It usually only affects the TDP of your CPU, which basically determines how much heat your CPU will produce. Examples are 32nm, 14nm, etc.
- L3 Cache: Has an impact depending on how CPU bound the game or software is.
- Cores: Pretty self explainatory. The number of physical cores the CPU has. Doesn't really matter unless you are comparing CPUs within the same architecture.
- Threads: Usually each core is able to handle 1 threat. However, with Intel's Hyperthreading and AMD's SMT, some CPUs can handle 2 threads per physical core. That in some cases, translates into better multithreading. Some other times in better performance, because of the way CPUs handle their cycles more efficiently.
- Speed: The same as cores. Can't be interpreted as the real-world performance the CPU has. There are many 3GHz CPUs better than 4+GHz CPUs. It really doesn't tell you much unless you are comparing within the same architecture.
Motherboard
The motherboard itself won't affect performance directly. Getting a better motherboard will not translate into, let's say, better FPS in a game. It can, however, limit the components you use, and the amount of overclocking you can achieve.
- Socket: This is the most important thing when choosing motherboards. You MUST make sure it has the socket to which your CPU belongs. If your CPU is a Kaby, you'll need a 1151 socket motherboard. This doesn't affect funcionality directly, but it has to match your CPU. Otherwise the CPU won't fit, and you'll have a problem.
- Chipset: Usually chipsets limit what a motherboard can do, or how a motherboard is designed. Some chipsets allow overclocking, others do not. Some allow Crossfire, others do not, and others handle it differently (such as the X370 and B350 motherboards from AMD).
- VRM: The voltage regulator module is a very important part of the Motherboard if you are interested in overclocking. I've seen very few guides actually addressing this. They usually take the form of numbers, like "12+2", or "4+1". Some CPUs require a high phase count for a decent OC (like the FX lineup from AMD, because of their high TDP, and some others do not). The VRM affects the way current is delivered to the CPU, splitting the load between the phases. The more phases, the cooler they run, the more overclock you get without experiencing instability (Blue screens and/or stuttering).
- Crossfire/SLI support: What it says. Whether if it supports SLI or Crossfire, and sometimes the way it does it. The best example are the AM4 boards (the X370 boards use 8 lanes for each card on Crossfire, whereas the B350 use 16 and 4).
- Supported RAM: The amount and speed varies from one motherboard to another. Generally they are so high you won't have to worry about it (usually 64/128Gb and 3000MHz+).
RAM
This is where your PC keeps the files you are using at the moment. If your PC runs out of RAM, it will use free HD space to store them, and your HDD (even SSD) is exponentially slower than the RAM, and will result in heavy performance losses.
- Interface: Can be DDR4, DDR3, DDR2, DDR, etc. DDR2 and DDR already are very outdated. DDR3 is still decent. All new boards use DDR4.
- Speed: Measured in MHz. For example 2400MHz. This, however, is not the real speed. The real speed is half of the labeled speed. In the 2400MHz situation, the real speed will be 1200MHz. RAM is usually advertised as DDRxxx/PCayyyy. Example DDR3-2400/PC3-12800. That means it has a frequency of 2400MHz and the max data transfer is 12800 MB/s, and it's DDR4.
- Size: Depends of what you are using the PC for. If you are gaming, 16Gb for now is perfect. For other uses, depending on how intensive, you may require more.
- Dual Channel: Technology that allows for the speed to be doubled when using different RAM channels in the motherboard. Requires at least 2 RAM sticks.
- Mixing different RAM sticks: ALWAYS make sure your RAM uses the same interface supported by the motherboard (you can't mix DDR2 with DDR3), also sticks MUST have the same timings and recommended voltages, or you'll have to spend some time manually tweaking them. If you get something with different speeds, your motherboard will automatically downclock the faster stick to match the slower one.
Storage
Basically when choosing storage, the standars is to get: 1 SSD and 1 HDD. All you need to know is SSDs are faster (faster read and write speeds), but a lot more expensive (a 250Gb SSD costs from $80 to $150 or more) and HDDs are slower, but their price/Gb ratio is much better (1Tb HDDs can be as low as $50). Couple of thngs you have to know about both:
- Interface: Both SSDs and HDDs use SATA (SSDs also use M.2). You have to make sure your HDD is SATA 6Gb/s and not something else. Older drives have SATA 3Gb/s, SATA 1.5Gb/s, etc. This does not mean they have 1.5Gb/s write and read speeds, but rather 1.5Gbit/s, which translates into 150Mb/s (1Gbit =~ 119Mb).
- Rotation speed: Measured in RPM, it basically tells you how fast is your HDD. The standard is 7200RPM. This does not apply to SSDs since they do not have any moving parts.
- Cache: Not too important. If you can, get something with 64Mb, otherwise 32Mb will be all right. Theoretically will help you load programs faster.
GPU
This one is rather simple. It all comes down to how much money you put into it. Some have a better price/performance ratio, but essentially that's how it works. The same as CPUs, you can't use specs alone to compare cards with different architectures. Some of the specs are Core speed, Memory clock, CUDA cores, amount of VRAM, etc. The only one that could be a limiting factor is VRAM. The higher your resolutionm, the more VRAM you need. For now 4-6Gb should be allright for up to 4K resolutions when gaming. The best way to compare cards is by using Benchmarks (userbenchmark.com being my favourite). Just to be clear I'll explain what VRAM does.
- VRAM: It's the memory of your GPU, where the card stores the textures rendered. If you run out, it will start using your system's regular RAM, which is exponentially slower and you'll loose a great deal of FPS. Having enough VRAM is incredibly important (if you run out of RAM too, you'll start using disk space, and that's way slower).
PSU
The PSU is a very important component, often neglected. The biggest problem with PSUs is the lack of information provided by the designers, and the deceitfullness of the 80plus certifications, which ARE NOT A MEASURE OF QUALITY. There is only two ways to know if a PSU is good: You open it up, and check it yourself, or, you can leave it to the pros. JonnyGURU.com is an amazing site with plenty of reviews, and he is a firm oppositor of the so called "PSU tier lists". So am I. The problem with this lists is the lack of context. Now to understand his reviews there are some things you gotta keep in mind.
- Date: If a PSU got a good final score, but when you look at the date it's 7-10 years old, chances are the unit is not as good anymore.
- Read everything: Don't just stick to the "recommended" units. Define a budget, find what decent PSUs are there (generally by looking at the most popular brands, like Corsair, EVGA, etc.), and then investigate each model.
That would be the end. For the case just pick something you like and that fits everything you need (DO NOT get a case w/PSU, they are usually terrible). Next I'll leave a link to some gaming and productivity builds.
Build guide