Home lab computer requirements
If you want to buy a new PC, laptop, or server what kind of hardware should you get?
You can answer this question if you know what kind of labs you want to run. Do you want to emulate regular IOS routers and switches? Or some more advanced devices like the Cisco ASA firewall or CSR1000v router?
Virtual Network Devices
Here is an overview of requirements for different devices:
Virtual Machines and Containers
Besides network devices, you might want to run some virtual machines or (docker) containers. This can be something lightweight, like a docker container to test freeradius. This only requires a few MB of RAM.
Some virtual machines might require a lot of vCPUs and memory. For example, the Cisco SD-WAN images:
The Cisco SD-WAN controller images require about 8 vCPUs and ~ 20 GB of RAM in total.
If you want to run a simple lab with 4x IOSv routers and 2x IOSvL2 switches, you'll need about ~3.5GB of RAM. That's not too bad. If you want to run 4x CSR1000v routers, you'll need 4x 3GB = 12GB of RAM.
Keep in mind you also need RAM for your OS (Windows, Mac OS, or Linux) and some other applications that you use.
vCPUs are usually not the issue. For example, consider the Intel Core i5-10600 Processor. This CPU was released in 2020:
This CPU has 6 physical cores and 12 threads (vCPUs). There is no "reservation" for vCPUs, a CPU like this can run a lot of virtual devices without running into any issues.
The number of vCPUs is usually not the bottleneck.
vCPUs are usually not the problem, memory is. If you are just getting started, I would at least get something with ~ 8 vCPUs and 16 GB of RAM.
You also have to consider the device that you are going to use. If you want a beefy laptop with Intel Core i9 CPU and 64 GB of RAM, you pay a premium price.
You can also go the "server" route. You can buy a used server with > 128 GB of RAM and an older CPU with plenty of vCPUs. This costs only a fraction of the price of a laptop, and gives you all the resources you need.