Warashi“How much RAM do I need?” is the most common question before buying a Mac, and the most guessed. The honest answer is: as much as your memory pressure says, not what “Memory Used” says.
Why “Memory Used” misleads
macOS treats unused memory as wasted memory. It fills it with file caches and keeps apps' memory compressed instead of throwing it away. So a Mac showing 15 of 16 GB “used” can be perfectly happy.
What to look at instead
- Memory pressure: green, yellow or red in Activity Monitor's Memory tab. This is macOS telling you how hard it's working to find memory.
- Swap used: memory written out to the disk. A little is normal; gigabytes of it every day means you're short.
- Compressed: memory squeezed to fit. High compression with pressure rising means you're near the edge.
Rules of thumb
| What you see over a typical week | What it means |
|---|---|
| Pressure green, swap near zero | You have enough. More memory won't make it faster. |
| Yellow on busy days, some swap | You're at the limit. The next Mac should have one size more. |
| Yellow or red most days, swap in gigabytes | You're short. One or two sizes more. |
Measure, don't guess
The catch is that you need a week or a month of this, on your busiest days, not a glance on a quiet afternoon. Warashi's Upgrade Advisor records memory pressure and swap every day and, after 30 days, recommends a memory size Apple actually sells, with the evidence.
Warashi does this for you. It records your Mac's history in the background, so you can look back at what happened instead of trying to catch it live. Join the waitlist →