By the end of this guide, you should be able to pick out what is a good fit for running a Homelab.
You don't need to supply each part to build your own computer, but knowing what parts are good for a Homelab can help you determine if that Ebay or Facebook Marketplace listing is a good deal or not.
The CPU should be one of your main considerations when acquiring a computer. The specification of a CPU will determine how well it can handle lots of containers or an intensive load.
There are some general guidelines to follow, though there are some exceptions:
If you just want a recommendation without justification refer to this:
If picking Intel:
If picking AMD:
As always, newer will almost always be better. But keep in mind that newer CPUs will be more expensive and other components they require might be more expensive.
More cores are better up to a point. Many CPUs have hyper-threading, which allows them to have 2 threads for every core. This allows them to handle lots of services and containers better.
Processes wont use more than a few threads, even if they are available. Generally, the only way to be able to utilize more cores is to have more services running. Keep in mind that a 4-core processor can handle many services/containers just fine.
As a general rule, anything older than Haswell Generation (4th Generation Intel) isn't recommended. The performance of CPUs older than these can be limiting.
For AMD, anything before Ryzen isn't recommended. CPUs before Ryzen from AMD had many cores, but the cores were very slow and limited compared to their counterparts.
If power usage is a factor to consider, then a CPU with a lower TDP (Thermal Design Power) will be better. 65 watts is the standard for most entry-level to mid-range CPUs.
Memory/RAM will be a common upgrade for repurposed office computers for turning them into Homelabs. Most office computers will only have 4-8 Gigabytes (GB) of RAM, if it has any.
Barring some exceptions, CPUs can only use one kind of memory/RAM - DDR3 or DDR4. Be sure to check the CPU and motherboard compatibility to ensure you secure the right kind of RAM.
If buying DDR3, you will most likely need to buy used on Ebay or Facebook Marketplace. A 16GB kit is currently around $20.
If buying DDR4, you can still buy new on sites like Amazon. A 16GB kit is currently around $25-30.
Generally not. The use cases for a discrete GPU in a Homelab are not much.
TL;DR Suggestion: Intel Arc A310 from Amazon
If you decide you need a GPU, any Intel Arc Card will do very well, is available new, and supports AV1 encoding. If you want NVIDIA, a card from the GTX 900 or GTX 1000 series will suffice.
SSDs have come down in price majorly in the last few years, and are significantly faster than HDDs. For this reason, using an SSD for your boot drive is recommended.
The amount of storage you need will be very dependent on the applications you will be using in your Homelab.
Most computers are guaranteed to come with an Ethernet port that supports 1 gigabit speeds (125MB/s). This is generally more than enough for any application.
WiFi can work fine for some applications and basic connections, but using Ethernet is recommended for its increased stability and transfer speeds. WiFi being a wireless standard means it can be prone to dropped packets and interruptions in the connection.