How To My Comprehensive Guide to Buying Used Components

I don't know if this has been done before, but since google search returns are nihil, I am just compiling on the things that I know from experience and my research that I have casually done for the past few years. Feel free to disagree with me, I am always looking for inputs and am always ready to debate on things I find interesting. Also, I don't know if this is posted on the right section, because I can't find any other ones that fits this beside the classified section. But that section should not be for something like this, right?

Why Should I Buy Used PC Parts?

I can think of two main reasons why you would want to buy used PC components. The first reason is that buying used is to put it simply, cheaper. You can potentially get tons of great deals, getting something that would have cost twice the price if bought brand new.

The second reason is that some items are old, discontinued, and not retailed anymore. A great example of this is older LGA 775 or AM3 CPUs. There are many instances where upgrading the motherboard doesn't make sense, and the only reasonable option is only to upgrade the CPU. Since very few are selling brand new older hardware, the used market could be the only option.

Where should I buy used components?

There are two kinds of sellers. The first one is the individual sellers. They are regular PC users like many of us, selling components for many different reasons, such as upgrading to new hardware, trying to pay a loan in a brink of a deadline, or ditching the PC altogether for other entertainment systems. These sellers don't sell many things and usually sell very specific items or an entire rig. I prefer buying from this kind of people, because they usually have more information about what they sell than the second kind.

The second kind of sellers are people that sell used stuff for profit. These people buy used parts from other people and resell it to you for their benefit. Resellers typically don't give as much information as the first kind, but that doesn't mean they always give worse deals. Make sure to compare prices carefully, and always ask for as much information as possible; there's a chance that they know the things they sell well.

I don't typically give recommendations to what platform / website you should use because it is different from region to region, but I'll try to explain what I want to say here. There are platforms better suited for personal sellers, such as the Facebook Marketplace, Craigslist, forums such as this one, etc. The second kind generally sells their things in a more built-up website such as eBay or Amazon. Some platforms also offer a cashback guarantee if the seller fails to deliver their promise. The thing is, I don't know which one is best, as I've only exclusively used a local platform that isn't available worldwide. But, whatever you use, just beware of scams. I've heard tons of scam stories from Craigslist, so be extra careful there.

How to determine if the seller is good?

The easiest thing to determine how good a seller is is by asking them questions regarding the components they sell. A good indication of an honest seller is that they are willing to give as much information as they possibly could. Another good indication could be that the seller knows the PC hardware well and is willing to help you with accurate answers. If the seller is not interested in answering your questions or give tips or responses that are against the consensus of the PC community, it may be an indication that the seller isn't someone you should trust.

It is also helpful to work with the information that is available around the seller. If you are buying parts using platforms such as eBay and Amazon, check their profile and ratings and success rate. If you are using Facebook Marketplace or Craigslist, check their profile. Ask for a phone number and look it up online whether or not the number is related to a previous scam.

How to check for yourself?

If you are not sure about the details the seller provides, you can check on your own. However, there are some things that you might want to be careful. The case and peripherals can be tested in any system or even without any other components. CPUs, RAMs, motherboards, monitors, Coolers, and GPUs are fine to test out on your PC, given that you have the compatible hardware.

Storage devices are a bit more complicated because you have to wipe the data clean before you run it alongside the other drives. It might risk infecting your other drive. PSUs, on the other hand, are pretty risky to test. Unless you have a load test kit (which, of course, most of us don't), don't test PSUs that you are buying from a shady seller / make on your hard-earned PC.

What parts should I be buying?

Some parts are much easier to check than others when it comes to the used market. I'm going to classify them into four different tiers on what you should watch for when buying.

Tier Super Easy: Only basic functionality checks are needed

I'll be surprised if you don't think that the case is the safest component to be bought used. The case has minimal electronics in it, and any potential issue could be detectable quickly by simple questions or physical examinations. Make sure to check the functionality of the front-panel connectors and check for physical marks such as dents, cracks, or scratches so you can dictate the price better. Typically, it doesn't matter how old a particular case is. Though, the fans might need replacing if they are over seven years old, but that's very easy to do and not that expensive.

Air Coolers / HSF: Air coolers only have the fans to worry about, as the heatsink practically lasts forever. Good quality fans, with superior bearing types such as SSO and Fluid-Dynamic, are usually OK for years of heavy usage. As long as they run without any noticeable abnormality, they are generally acceptable to buy. Inferior bearing types such as sleeve are harder to determine. But with cheap HSFs such as the DeepCool Gammax 400 V2 selling for $20, I doubt you'd want to bother with low-quality, second-hand, air coolers.

Peripherals (keyboard, mouse, headset, speakers, chairs, tables): Like the case, these parts contain minimal electronics on them, and the primary building mechanisms are usually mechanical. Just double-check on the functionality of these components. For example, if you're buying a keyboard, make sure that every key work. Similar to the case, age isn't something you should worry about here.

Tier Easy: The components have strong resilience from damage. They are almost always safe to buy if they work as they should. Some tests are still required to confirm their functionality

The toughest electronic part in the PC. The structure of CPUs is simple and doesn't leave much room for breakage. So, almost in all cases, CPUs are pretty much binary, meaning they either work perfectly or entirely junk. I've never seen in my personal experience a CPU that would POST but crashes all the time booting into windows. So, as long as a CPU can boot, does not overheat abnormally, and has no physical signs of damage, it should be clear. Aging should not be a problem. I have never seen 20-year-old Pentium IIIs failing with proper usage, so CPUs can stand the test of time.

RAMs: The second toughest after the CPU. The RAM only consists of memory chips and a small PCB, so it is structurally more complex than CPUs but much simpler than other components such as GPU and Motherboards. Like CPUs, RAMs are almost always binary, but I've seen RAMs that can POST but struggles in heavy loads. So, besides the regular POST test and physical examinations, ask the seller to do extra tests such as Memtest and a long, stressed run of Prime 95. These tests should confirm whether or not the RAM is working fine. Since RAMs gets too old to be available new before aging is a concern anyway, I doubt anyone should care about aging on RAMs. They are, however, not as resilient as CPUs.

Tier Medium: These components are safe to buy if the item performs as it should, but with a few caveats. Aging and warranty could come into play as to whether or not these components are acceptable to buy. The components are more complex than the easy tiers, and judging their condition isn't as easy.

SSDs are structurally similar to RAMs, but they are not made to withstand cycles of data written and erased on them as often as RAMs do. Manufacturers of SSDs typically specify how much data can be written on the disk before it fails. So, besides the regular POST, booting, and stress tests, it would be helpful if the seller can post a screenshot of CrystalDiskInfo to check the condition of the SSD. The total NAND write is displayed there, and you can compare it to the manufacturer's specification.

Other than the total written data, the age of the SSD is also relevant. Avoid over 7-year-old SSDs; they are too old to be worth it. Warranty is also an essential feature in SSDs, so having a transferred warranty from the seller is a bonus in case the drive fails. As a general rule of thumb, you should never be paying more than 75% the cost of getting a new, comparable SSD.

GPUs: GPUs have many components that make them up. The GPU consists of the GPU chip itself, Memory, VRM, PCB, and Air Cooler, so it is bound to more failures than other components. There are piles of GPUs that can work fine in light workloads but fails in heavy workloads and a long period of gaming. So, other than the regular checks such as POST and physical examinations, always check for their stability. Verify that it can indeed work in at least an hour of heavy workloads on a benchmark such as Unigine or 3D Mark without crashing or overheating.

Age can also be an influential factor on GPUs. Less than 3-year-old GPUs are going to be much better than much older GPUs, so ask the seller when the GPU was purchased. Plus, you should also ask what precisely the GPU was used for. Because of the recent Ethereum boom, I have seen a ton of ex-mining, used GPUs on the market. In my opinion, ex-mining GPU should be 25-40% cheaper than regular GPUs, because their chance of failing is substantially bigger.

I also wouldn't buy a used GPU if there's a new GPU that can perform within 10% of its performance. For example, a used GTX 1080 Ti should be below the price of a brand new RX 5700 XT if it's under three-year-old. If the used GPU is older, it should be lower than the price of a new GPU that can perform within 20% of its performance, such as the GTX 2060 Super or the RX 5700. There's a comprehensive guide of performance on different older GPUs here.

Motherboards: Like GPUs, a multitude of things make up a motherboard, so it is prone to damage. However, I put it lower on this tier. Unlike GPUs, it is hard to determine if there is anything wrong with it. It isn't exactly easy to determine if something is wrong by stress tests alone. So, checks on physical condition, function of all the sockets, slots, ports, network, sound, and the age give more information on the condition of the motherboard.

This difficulty is the reason why I wouldn't recommend anyone paying a used motherboard with more than 60% the price of a new one. For older, discontinued motherboards, this is harder to determine, as you have no other options. Though, you can get discounts if you found that the motherboard has limited functionality.

Monitors: I am not good with monitors, so excuse me for inaccuracies here. If I recall correctly, to find out whether a monitor is buyable or not, you should only be doing dead-pixel tests and discolouration tests. Brightness, contrast, and vibrancy might also degrade over time, so if you care about the image quality, don't buy used monitors that are too old (>5-year-old).

Tier Avoid: Avoid if not dirt cheap

HDDs are a mechanical component that are pretty easy to break. They have varying times of failures. Some break within weeks, others some can go for decades without problems, so age can't be a determining factor. Moreover, HDDs are cheap, so if it isn't dirt cheap, there is no reason to buy them used.

PSUs: PSUs are complicated components. They are the most critical part of the PC, yet they are very difficult to test. To simplify my advice, I'll be straight to the point here. Don't buy budget, used PSUs. Only PSUs that come with at least a seven-year warranty are worth buying used. They must have at least Silver efficiency, 105C rated capacitors, at least rifle bearing fans, and have reliable reviews. You are better off buying new if they are budget or no-name PSUs.

Always ask for what kind of system the PSU had been powering. PSU components degrade quicker on systems such as mining rigs and home servers. These PSUs should be much cheaper than PSUs used in normal circumstances. The age of the PSU should also be checked because I don't think it's a good idea to buy PSUs that are without warranty. Depending on the age and usage, I'd pay 40-70% the normal price if a good, seven-year-plus warrantied-PSU is still under warranty. Otherwise, just buy new and don't risk your hard-earned money.

Liquid Coolers: I am one of those guys who thinks that no liquid should be on any kind of electronics, so call me biased. I think the risks are too significant buying a used liquid cooler, so I don't see any reason why you should buy them.

Phew that was a whole wall of text. I hope this article helps you with your buying decisions. Until next time.
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