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The M5 MacBook Pro still starts with 16GB of RAM, and I keep getting the same question: is it finally time to start the Pro at 24GB instead? So I put the two side by side. One is the M5 MacBook Pro with 16GB of RAM and a 512GB SSD. The other is the 24GB model with a 1TB SSD. I wanted to see the real difference between them and figure out whether spending a little more on memory does more for you than you would expect.
The 16GB base model holds up better than you might think, but the roughly $200 jump to 24GB buys a bigger buffer that pays off in AI work, heavy multitasking, and a couple more years of useful life.
- 16GB baseline handles everyday multitasking well
- 24GB reaches yellow memory pressure much later (35 tabs vs 20)
- 24GB is dramatically faster for local AI in LM Studio
- RAM is not user serviceable, so buying up front matters
- You can go all the way to 32GB on the M5 if you need it
- Most benchmarks were close between the two
- The 24GB upgrade costs about $200 more
- Everyday browsing barely feels different between them
Intro: Who This Is For
This is for anyone standing in front of the M5 MacBook Pro configuration page trying to decide whether to click the 24GB option. If you mostly browse, write, and run a handful of apps, the 16GB base is going to feel fine. If you push into local AI models, video editing, 3D work, or heavy photo exports, this is where the extra memory starts to earn its keep. I tested both machines with the same tasks so you can see exactly where the line falls.
The two units are not a perfectly matched pair. The 16GB model has a 512GB SSD and the 24GB model has a 1TB SSD. I checked whether the storage difference was skewing anything, and I will get to that, but the short version is that the SSD was not the deciding factor in these tests.
What Unified Memory Actually Does
Before going further, it helps to know what the RAM is doing. Your CPU is incredibly fast and can write tons of data every second. The SSD is slow by comparison. So the RAM acts as a buffer where the CPU can quickly write things that need to be remembered temporarily. When something needs long-term storage, the computer moves it to the SSD.
The way I think about it, having more RAM is like having a bigger workbench. The more space you have on the bench, the more tasks you can get done without bumping into tools and materials that are in your way. More RAM gives your computer that bigger workbench, so it can keep more tasks readily available for the CPU. That improves how quickly you can switch between apps, or even between tasks inside the same app. RAM is the fast, temporary working space your computer uses for active programs. When you start to run low on it, the computer falls back on the SSD for those tasks, and that is when you feel the slowdowns.
Memory Pressure: Where 16GB Starts to Sweat
For plain day-to-day use, running multiple browser tabs and doing normal multitasking, I did not really notice the 24GB feeling all that much faster than the 16GB. The difference shows up when you push more intensive apps or drive the memory pressure higher.
So I opened Safari and Activity Monitor and started stacking tabs to see how long it would take to reach yellow memory pressure. On the 16GB machine, it only took 20 tabs to get into the yellow. On the 24GB machine, it took 35 tabs. Then I pushed both up to 50 Safari tabs. At that point the 16GB one was pretty mad at me. It was really not responding well at all. The 24GB machine had a lot more room before it started to struggle.
The AI Test That Made the Gap Obvious
Then I opened LM Studio, which is a pretty intensive app that lets you run AI models locally on the computer. I loaded GPT-OSS on both machines. Before the 16GB one could even load the model, it was already loaded on the 24GB machine. I had typed in a question and gotten a response with about five seconds to the first token on the 24GB. The 16GB one just kept spinning for minutes. I finally got tired of waiting and canceled the test.
That test told me something clear. If you really want to push these machines, running video editing or 3D rendering software and switching back and forth between apps, that is when you are going to appreciate the extra memory. You can go all the way up to 32GB on the M5 if you want, but even stepping up to 24GB made a huge difference here.
Time to First Token: The Number That Mattered
The benchmarks were not all lopsided. I want to be honest about the messy part of the test: the 16GB had a 512GB SSD and the 24GB had a 1TB SSD. But the disk speed results were very close in Blackmagic Disk Speed Test, so it did not seem like one SSD was simply running faster than the other. When I compressed large files, both machines finished in the same amount of time. Typically the extra RAM only gave a slight improvement in benchmarks.
The exception was AI work. Back in LM Studio with GPT-OSS, the big difference was the time to first token, which is how long the computer takes to process the request you give it. On the 24GB machine, that was two to five seconds. On the 16GB machine, it was 12 to 15 seconds. The 24GB also generated a few more tokens per second, though that figure ended up pretty close. It was really the time to first token that separated them.
I found a few other tasks leaned the same way. Compiling code was a little faster on the 24GB. Exporting a scene from Blender was a little faster too. The one that surprised me was a Lightroom Classic export of 500 RAW photos to JPEG. That took about 3 minutes and 18 seconds on the 16GB. The 24GB sped it all the way up to 1 minute and 54 seconds. That may just be how Adobe apps run, leaning on the RAM more than the CPU. So depending on the apps you use, if some of them lean on memory for processing, you are going to notice a real difference. Most of my other tests were pretty negligible and both machines performed very closely.
| Test | 16GB | 24GB |
|---|---|---|
| Safari tabs to yellow memory pressure | 20 tabs | 35 tabs |
| LM Studio time to first token | 12 to 15 sec | 2 to 5 sec |
| Lightroom export, 500 RAW to JPEG | 3 min 18 sec | 1 min 54 sec |
| Blackmagic disk speed | Very close | Very close |
| Large file compression | Same time | Same time |
Is 24GB Worth the Upgrade?
It costs about $200 more to take the MacBook Pro from 16GB to 24GB, and I think it is worth it. The RAM is not user serviceable, so you cannot add it later. Buying up front is the only shot you get. The 24GB gives you a bigger buffer and keeps memory from filling up as fast with modern apps or heavy multitasking, and that should also give you a couple more years of useful life out of the machine.
All in all, I was still pretty impressed with how well the 16GB held up. There is a reason Apple is making 16GB the baseline for its modern Macs. But the 24GB gives you that extra headroom for now and for the future, as applications keep getting more memory intensive and as more AI features arrive. If you want to save a little more, B&H is an Apple authorized retailer that often has strong sale prices, and the Payboo card can knock the cost down further.
The Bottom Line
The 16GB M5 MacBook Pro is genuinely capable, and for everyday work you may never feel a wall. But the 24GB model reaches memory pressure later, chews through local AI far faster, and handles memory-hungry apps like Lightroom with real gains. For roughly $200 on a part you can never upgrade, the 24GB is the configuration I would buy for peace of mind and a longer useful life. If you are running AI models, editing video, or doing 3D work, do not think twice about it.
