Does RAM usage change with what's installed?

[slowlife]

I just got a 2017 MBP 15 inch right before the announcement of the new model. This MBP has 16GB RAM. Currently, I have the following apps open:

• Safari (2 tabs)
• Chrome (3 tabs)
• Mail
• Outlook
• Messages
• Adobe Acrobat
• LINE
• Powerpoint
• Activity Monitor

The activity monitor is showing Physical Memory 16GB, Memory used 12.12GB. Cached files 3.47GB.

So if I had bought an 8GB 13 inch MBP or MacBook Air, then my Mac would have crashed? I want to buy the new 2018 15 inch model of the MBP now, therefore, so I need to order 32GB RAM?

Thanks for your input.

 

[leman]

So if I had bought an 8GB 13 inch MBP or MacBook Air, then my Mac would have crashed? I want to buy the new 2018 15 inch model of the MBP now, therefore, so I need to order 32GB RAM?

No and no. You’d most likely be perfectly fine with 8 GB. The system tries to use as much RAM as possible, for example for optional data that might accelerate operation. This doesn’t mean that the figures you see are the absolute minimal amount of RAM required to run these apps properly.

 

[airlied]

I just got a 2017 MBP 15 inch right before the announcement of the new model. This MBP has 16GB RAM. Currently, I have the following apps open:

• Safari (2 tabs)
• Chrome (3 tabs)
• Mail
• Outlook
• Messages
• Adobe Acrobat
• LINE
• Powerpoint
• Activity Monitor

The activity monitor is showing Physical Memory 16GB, Memory used 12.12GB. Cached files 3.47GB.

So if I had bought an 8GB 13 inch MBP or MacBook Air, then my Mac would have crashed? I want to buy the new 2018 15 inch model of the MBP now, therefore, so I need to order 32GB RAM?

Thanks for your input.

Just like the other guy said, your mac uses as mush ram as possible. If the physical ram is ‘insufficient’, mac will swap some data that are not likely to be used to hard drive.

This swap thing had been a big issue before since hdds are usually slower, when CPU needs to access those RAM data on hdd it takes significantly longer time than just putting out from RAM. but new macs come with faster SSD (which usually achieve 1800mb/s + read/write speed), so this issue is not that big anymore.

But it doesn’t mean RAM size is not important at all. Remember, What makes memory so important to system is not the ‘speed’ itself, but ‘random access speed’, which is how the RAM (random access memory) got its name anyway. Random access speed on RAM is still significantly fast than that on SSD.

So don’t pay too much attention on how full your RAM usage looks like, if you don’t feel slow then it’s fine. but if your swap files is too big you may consider 32gb ram.

 

[keysofanxiety]

I just got a 2017 MBP 15 inch right before the announcement of the new model. This MBP has 16GB RAM. Currently, I have the following apps open:

• Safari (2 tabs)
• Chrome (3 tabs)
• Mail
• Outlook
• Messages
• Adobe Acrobat
• LINE
• Powerpoint
• Activity Monitor

The activity monitor is showing Physical Memory 16GB, Memory used 12.12GB. Cached files 3.47GB.

So if I had bought an 8GB 13 inch MBP or MacBook Air, then my Mac would have crashed? I want to buy the new 2018 15 inch model of the MBP now, therefore, so I need to order 32GB RAM?

Thanks for your input.

The more RAM you have, the more macOS will utilise when idling for the best performance. Back in the older days with user upgradeable RAM you'd see the usage shoot way up when you'd upgrade from 2GB or 4GB to 8GB. Give it more resources and it'll gobble it up, which helps performance. As long as it's not paging to disk, you're fine.

This is really great compared to Windows which doesn't really upscale resource usage when you upgrade RAM, so you rarely see any great performance benefit with medium usage. Windows still uses the same paging to disk & RAM when you load or run an application, which is hugely frustrating. Free RAM is wasted RAM.

 

[leman]

This is really great compared to Windows which doesn't really upscale resource usage when you upgrade RAM, so you rarely see any great performance benefit with medium usage. Windows still uses the same paging to disk & RAM when you load or run an application, which is hugely frustrating. Free RAM is wasted RAM.

Windows does the same these days, really. Its just that Windows reports used RAM differently. And to make matter more complex, processes can share actual RAM, even though it would appear to them that they have their own memory. You can have dozens of processes allocating hundreds of GB of RAM, when 95% is actually shared data.

To see how complex the entire system is, run vm_stat in terminal. That will give you a taste

 

[MrGunnyPT]

I use a 13" MBP TB 2017 every day with 8GB.. I usually have 3-4 or tabs open in both Safari & Chrome alongside a Linux and a Windows VM going on.

My RAM pressure is usually 55%.. So far so good and I don't have a single issue.

Next time around i'll buy a 15" for the dGPU thou, I do wanna play some games from time to time and this Intel HD GPU is a mess for it.

 

[slowlife]

thanks everyone. If these are the programs and tasks that I generally use, then 32GB RAM is a waste of money?

 

[leman]

thanks everyone. If these are the programs and tasks that I generally use, then 32GB RAM is a waste of money?

I'd say stick with 16GB unless you work with high-res video and/or data sets that need to be resident in memory (e.g. if you are doing statistical analysis on multiple-GB datasets and your software doesn't properly buffer data).

 

[MrGunnyPT]

16GB is the sweet spot these daus

 

[jerryk]

The Memory Pressure graph on Activity Monitor' Memory Tab, https://support.apple.com/en-us/HT201464#memory, is the one to watch. If it is green you are fine. If it is turning yellow or red, then you need more memory.