The Computer You Have Will Probably Work
Most modern computer CPUs are more than capable for large audio projects if the RAM and disc drives are up to snuff. If you have a computer that's less than 7 years old or so, it will probably work for recording.
If you have a computer already, I'd suggest you load Reaper up on it, grab a mic and audio interface, and give it a go. If you run into any problems, you can look to the info here to give you a clue as to what you might need to upgrade.
You might have to bump up the RAM, or add a hard drive to your old workhorse (I eventually did both to my laptop). Check out the recommendations below and adapt them to your situation.
Bare Bones, Mid-Level, & Heavy Use
I'm going to divide my recommendations into three main categories -- Bare Bones, Mid-Level, and Heavy Use. Your gear recommendations will depend on which category you fall into. Check them out, and decide where you fall, and click on the appropriate tab for your situation.
Recording yourself and your acoustic guitar? Are you a folk duo with banjo, accordion and two vocals? Do you imagine you'll record just a few tracks, with standards effects, such as reverb, delay, & compression?
Lean toward the bare bones recommendations.
- 8Gb RAM (4, but that's stretching it)
- CPU: 1.5GHz, single core (or better)
- Drive Use: 240 - 500Gb internal HDD
Are you a solo musician who wants full band arrangements? Do you imagine yourself using virtual drums, bass, or guitar? Do you think your track count might be 20 or more tracks? Will you use amp sims to get your guitar sounds, rather than a mic in front of an amplifier?
Mid-level is probably where you're at.
- RAM: 8-16Gb of RAM
- CPU: 2Ghz or better processing speed, dual core -- or better
- Drive Use: 500Gb SSD for OS, separate, external or internal 500Gb HDD or SSD for Audio files
Do you want it all? Lots of synthesizers, lush orchestral arrangements, amp sims, and effects. Are you going to double your guitar tracks 8 times? Do you want to livestream your recording sessions from the same computer?
Heavy use is where you'll want to look.
- RAM: 16Gb or more
- CPU: 3Ghz or better processing speed -- quad core, or better
- Drive: 1Tb SSD for OS, Separate 1Tb internal SSD for Audio files
What Specs Are Important? It Depends . . .
For a computer running a DAW, CPU, RAM, drive performance and drive space are important. Which is more important will depend on what kind of recording you'll be doing.
Amp SIMs (which imitate the sound of a guitar amplifier and fx) use lots of CPU, but not much RAM. Sample based virtual instruments (VSTIs) often use lots of RAM. Synths are RAM light. Normal audio recording a playback of audio files uses little RAM, and not that much CPU. If you're recording many tracks of mics at once (a live drum kit, for instance), drive write speed is important (an SSD is preferred).
So . . .
You might need more CPU if you . . .
- Use amp sims for your guitar sounds
- Use a lot of effects
You might need more RAM if you . . .
- Use a lot of VSTIs (orchestral plugins, virtual guitars, basses, pianos, percussion etc.)
You might need an SSD to record your audio files if . . .
- You record a lot of tracks simultaneously (such as 8 or 9 mics on a drum kit)
What About Drives?
As a general rule, SSDs are recommended for your OS. Install your DAW on an SSD. If you have large sample libraries, they should probably reside on an SSD (or maybe flash memory). Old fashioned hard drives are OK for audio, but SSD is preferred. If you go old school, 7200 rpm for your drive.
For backup and archiving, you don't need an expensive, or fast drive. Grab anything reliable that is big. I recommend one onsite backup and one cloud backup of your sessions & audio.
In general, you'll get more bang for your buck with AMD Ryzen CPUs, these days. Intel will do, though (I've been running mid-level sessions on an i5, for several years, now). If you buy something near the top of the line that's about to be replaced by a new model, you can score a deal. M1, for Mac is the bomb, I hear.
In terms of speed, single core speed is more important if you're running a light session, but multiple cores become more important as your session becomes more complex.
How Do You Prioritize Between CPU, RAM and Drives?
Well, CPUs are a bit if a hassle to upgrade, whereas it's pretty easy to have your local computer shop pop in some new RAM. If your internal hard drive is an SSD, you can run your DAW there and easily get an external drive (or internal, if you have a slot) to add storage space.
So, err on the side of CPU performance, if you don't know which way to go. Make sure though, that your RAM is upgradable, or has additional slots.
My laptop is old enough to have a CD/DVD drive. I never used it, so I found what was called a drive caddy. The drive caddy allowed me to replace the CD tray with a drive tray, and pop an additional 1Tb SSD drive into my laptop.
USB or Thunderbolt Port Availability: I always run out of these. Make sure you have plenty of ports.
Noise: My old laptop wheezes like a 90 year-old smoker. I'm forced to move my mic further away while recording, which is inconvenient. There are quiet fans, quiet cases, and CPU coolers available, which can help.
Screen Size: 15" or better. My laptop has a 15.6" screen, and I've got to admit it's challenging for me to fit everything on the screen and still be able to see it. Some people use a dual monitor setup, this freeing up space on the main screen.