[ghshephard]

I have 8 GB of memory on my 2013 13" MBook Air - I run 23 separate applications simultaneously, including the full office Suite (Outlook/PowerPoint/Office/Excel), VMware Fusion w/Windows XP + OpenBSD running, Dynamips Routing Simulator w/10 Cisco 7200 routers, Google Earth, Aperture, Pixelmator, etc.... No swapping. Everything runs fine.

OS X (in my case, Mountain Lion, so an old version) - does really, really well with shared libraries. 95%+ of consumer users (not pros, whose needs are obviously more rarified, and for whom the sky is the limit) are probably fine with 8GB of memory, and it's not something I would recommend them increasing unless they plan to hold onto the computer for more than 5 years.

[lprez]

Yosemite beta 6, just booted with only Firefox and this HN page open takes already 2,8GB. Yosemite is really memory hungry compared to Mavericks in my experience. And future version are going to get hungrier. Those 8GB are going to fall short within the next 2 iterations of OSX, an after paying $2500 that feels ridiculous to me.

[astrange]

> Yosemite is really memory hungry compared to Mavericks in my experience.

Which numbers are you reading for this? The "memory use" total includes lots of irrelevant things like files read once during boot and optimistically cached for later, so you can expect it to be nearly 100% of installed memory at all times.

You're not in a memory pressure situation until you have an actual performance problem or the swap space starts growing.

But if you are having performance problems, I'm pretty sure someone cares deeply about them and would like to know the per-process memory use.

[ghshephard]

Mountain Lion 10.8.5 - fresh boot with only Chrome and this HN page open - Used: 2.83 GB.

Once the shared libraries are in memory, memory usage grows really, really slowly for my application set (listed above) on OS X.

I'm not saying that 8 GB will last forever - I'm just saying, as a power user who has zero need for more than 8GB right now, that 8 GB on OS X will be just fine for about 95% of average consumer use. Absolutely would not recommend upgrading an iMac's memory unless you are really certain you are going to hang onto it for more than 5 years - not the best use of $200.

I'm just talking about your average family use; for vertical niches (Video Work, Graphics Design, Heavy Industrial Programs, Databases) - obviously those people will assess their situation and make a decision that is optimized for their circumstances.

[megablast]

Memory does not work the way you imagine it does. OS do not optimize for keeping memory empty.