Anyone running 12-16 GB RAM in their Mac?

[Eug]

The machine I'll be getting is supposed to be coming with 2 x 4 GB DDR3 1333 MHz SODIMMs, which means I'll have two empty slots. I was surprised to see that another 8 GB of RAM would only be about $125.

However, I'm thinking 16 GB is overkill for just about anything I do. The only thing I really do that is RAM heavy is Aperture, but so far 8 GB seems to be fine with it. However, another 4 GB RAM is only $60, which would bring me up to 12 GB.

Anyone here have 12-16 GB in their Mac? If so, for what purpose?

 

[PCTC2]

I have a 27" iMac with 16GB of RAM and at work I have a Mac Pro with 12GB of RAM as well. They're mainly used for web development, package testing, and running virtual machines (RHEL and Mac OS X Server). Mainly the VMs and web development software take up most of the RAM.

 

[Eug]

Aside from the memory for the virtual machines how much memory do you think you need? 8 GB?

Mind you I'm thinking that having 12 GB will mean that even with other people logged in and Aperture and Photoshop loaded I'll have minimal disk use.

Too bad Apple doesn't have Windows-like disk caching using RAM.

 

[Compman55]

In my opionion, and this opinion has stayed with me since 1993 when computers shipped with 2MB, you can never have too much ram or hard drive space. Buy the max you can afford.

If you even plan to dual boot windows 7 in the future, you are good to go.

 

[Nothinman]

Aside from the memory for the virtual machines how much memory do you think you need? 8 GB?

Mind you I'm thinking that having 12 GB will mean that even with other people logged in and Aperture and Photoshop loaded I'll have minimal disk use.

Too bad Apple doesn't have Windows-like disk caching using RAM.

The amount of memory you can use comfortably depends on your workload, no one but you can tell you what that number is. OS X uses memory for disk caching just fine, probably better than Windows in general, it's just that there's no equivalent to SuperFetch.

I have a Mac Pro with 7G in it and it runs just fine for everything I do, although I'm running Debian on mine.

 

[Eug]

The amount of memory you can use comfortably depends on your workload, no one but you can tell you what that number is. OS X uses memory for disk caching just fine, probably better than Windows in general, it's just that there's no equivalent to SuperFetch.

Please elaborate. (Yeah, I was specifically talking about SuperFetch.)

I did a brief google on it and couldn't find much on OS X's caching mechanisms.

In my opionion, and this opinion has stayed with me since 1993 when computers shipped with 2MB, you can never have too much ram or hard drive space. Buy the max you can afford.

If you even plan to dual boot windows 7 in the future, you are good to go.

I stopped using a Windows VM, as I just bought a second Windows 7 machine that sits in the same room as my iMac. So, I won't be dual-booting either. The Windows machine is mainly just for surfing, VPN, and Quicken.

 

[TheStu]

I just upped to 6GB, much better for VMs.

 

[Nothinman]

Please elaborate. (Yeah, I was specifically talking about SuperFetch.)

I did a brief google on it and couldn't find much on OS X's caching mechanisms.

Yea, it's annoyingly hard to find good technical information on OS X's low level functions. But in the general sense it's going to use a LRU algorithm like every other unix-like OS out there. Filesystem cache pages will be zeroed and reused as necessary based upon their age. And I don't believe there are any upper limits so any extra memory will be used for the filesystem cache.

 

[Kmax82]

I just upped to 6GB, much better for VMs.

Ditto.. if you're running multiple VM's.. the more RAM the better.

With Aperture 3.1 and a few minor other system utilities running, it can easily drop me down to 1GB free, but I haven't needed more than 8GB so far.

 

[Eug]

I've been mulling it over, and if AppleCare really does give me a 2 x 4 GB machine like they claim they will (instead of the 4 x 2 GB I was originally expecting), I will probably get another 2 x 2 for a total of 12. BTW, I'm surprised Apple even offered that to me, considering that it's normally a $200 upgrade on their configure-to-order website. Maybe they're trying to make up for the fact that I've been out my main computer for the past month... and memory is a lot cheaper these days.

While Aperture has been fine with 8, I've always made sure my GF's account is not logged in, and other memory heavy apps aren't loaded (like VMware when I used to use it).

With 12 GB it'd give me some breathing room. 16 GB isn't a hugely expensive upgrade either though, at only about $125, but it just seems like overkill.

Yea, it's annoyingly hard to find good technical information on OS X's low level functions. But in the general sense it's going to use a LRU algorithm like every other unix-like OS out there. Filesystem cache pages will be zeroed and reused as necessary based upon their age. And I don't believe there are any upper limits so any extra memory will be used for the filesystem cache.

So, I tried reading a few links I came across and unfortunately, while I superficially understand some of the basics, a lot of it is over my head. It'd be nice to know where bang-for-the-buck levels change.

But as I said above, maybe I'll just go to 12 GB cuz it's cheap.

 

[Nothinman]

So, I tried reading a few links I came across and unfortunately, while I superficially understand some of the basics, a lot of it is over my head. It'd be nice to know where bang-for-the-buck levels change.

But as I said above, maybe I'll just go to 12 GB cuz it's cheap.

The bang for the buck depends on how much a buck is worth to you. =)

I don't know if there's an Apple-specific book analogous to Inside Windows or Understanding the Linux kernel, but the latter is what I read in order to understand how the basic functions like memory management work.

 

[PCTC2]

I've been mulling it over, and if AppleCare really does give me a 2 x 4 GB machine like they claim they will (instead of the 4 x 2 GB I was originally expecting), I will probably get another 2 x 2 for a total of 12. BTW, I'm surprised Apple even offered that to me, considering that it's normally a $200 upgrade on their configure-to-order website. Maybe they're trying to make up for the fact that I've been out my main computer for the past month... and memory is a lot cheaper these days.

You can get 2x4GB around for like $150. It's not too expensive (I remember $300+ when I purchased). Apple doesn't really care about memory. I remember a while back where they literally had a trash bin in the back room for RAM. It was cheaper to throw it out than anything else.

 

[JSt0rm]

I'm rockin just 6gb. My software is still 32bit so it only addresses 4gb.

 

[Nothinman]

I'm rockin just 6gb. My software is still 32bit so it only addresses 4gb.

Probably 2G, I never looked at how OS X did their kernel/userland VM split. But even if that's the case you can still use the memory by running multiple things.

 

[LikeLinus]

Running 16GB in a Mac Pro 12 core. It's for Final Cut Studio and Adobe CS5. Good stuff and blazing fast.

 

[MrX8503]

I use an 8 core 10GB Mac pro at work. It's mainly used for after effects and final cut. With after effects it's recommended to have 2GB/core, so the Mac could easily use 16GB.

 

[JSt0rm]

Probably 2G, I never looked at how OS X did their kernel/userland VM split. But even if that's the case you can still use the memory by running multiple things.

It uses 4gigs. So 2 gigs for the os and whatever else. I never have ram issues.

 

[Kadarin]

8GB here in a 27" iMac that I use for SC2, Eve Online, and various other mundane tasks. No issues, and the i7 is pretty damned fast.

 

[intogamer]

I have a 27" iMac with 16GB of RAM and at work I have a Mac Pro with 12GB of RAM as well. They're mainly used for web development, package testing, and running virtual machines (RHEL and Mac OS X Server). Mainly the VMs and web development software take up most of the RAM.

Damn dude, you have a lot of computing power.

 

[dawks]

Just an FYI, only X-Serves (and maybe some new Mac Pros??) are configured to boot the 64bit kernel by default. You can boot a 64bit kernel by holding down 6 & 4 right at POST (the startup sound). Or make it persistant by running this command, "sudo systemsetup -setkernelbootarchitecture x86_64"
I did this on my 2008 Mac Pro (with 6gigs ram) and its working great.
Read here, http://support.apple.com/kb/HT3773

You can check to see if you're running the 64bit kernel by looking at the "Kind" column for kernel_task in "Activity Monitor". You'd see "Intel (64bit)". Or click on 'Software' in 'System Profiler' and look for '64-bit kernel and extensions'.

Also, was just browsing the Apple Dev site and came across this.. which says the 64bit kernel may provide some performance improvements, especially with larger amounts of RAM. (taken straight from the Apple dev page)

64-Bit Kernel
Mac OS X v10.6 includes a 64-bit kernel. Although Mac OS X allows a 32-bit kernel to run 64-bit applications, a 64-bit kernel provides several benefits:

The kernel can better support large memory configurations.
Many kernel data structures such as the page table get larger as physical RAM increases. When using a 32-bit kernel with more than 32 GB of physical RAM, these data structures can consume an unmanageably large portion of the 4 GB kernel address space.

By moving to a 64-bit kernel, the 4 GB kernel address space limitation is eliminated, and thus these data structures can grow as needed.

The maximum size of the buffer cache is increased, potentially improving I/O performance.
A 32-bit kernel is limited in its ability to cache disk accesses because of the 4 GB kernel address space limit.

With a 64-bit kernel, the buffer cache can grow as needed to maximize the use of otherwise unused RAM.

Performance is improved when working with specialized networking hardware that emulates memory mapping across a wire or with multiple video cards containing over 2 GB of video RAM.
With a 32-bit kernel, if the combined physical address space (video RAM, for example) of all of your devices exceeds about 1.5 GB, it is impossible to map them fully into a 32-bit kernel address space at the same time. To work around this limitation, driver writers must map smaller apertures of that physical address space into the kernel’s address space.

When such a driver needs to write to or read from an unmapped address on the device, it must unmap an existing region, then map in the new region. Depending on how the mappings are managed, this extra process may cause a performance penalty, particularly for clients that exhibit low locality of reference.

With a 64-bit kernel, the entire device can be mapped into the kernel’s address space at once. This improves performance by removing the extra overhead of mapping and unmapping regions of memory. It also removes the burden of managing these mappings in your driver code, thus making the drivers simpler and less likely to generate panics by unmapping the wrong memory at the wrong time.

 

[lokiju]

I'm running 8GB on my Pro and it's mostly helpful just for a VM I have on it. Otherwise it'd be overkill for just about anything else I could do.

 

[suklee]

I now have 12GB on my 21.5" iMac - the 8GB DDR3 I bought for my MacBook Pro didn't work so I had to stick it in the iMac :whiste:

 

[JSt0rm]

not all macs can run the 64bit kernal

http://en.wikipedia.org/wiki/Mac_Pro#Specifications

I just have the 2006 model. I wont upgrade this computer until I'm forced to via software upgrades that wont work on a 32bit osx anymore. A lot of composers who use protools want 64bit so they can load up massive amounts of samples in ram but I don't work with the software in that way so the 4gb limit is fine for me.

I run dsp cards in the mac as well but my cpu usually sits around 30% usage of 3 of the available 4 cores.

I find the situation to be absolutly awesome. When did we live in a time when a computer that is almost 5 years old just works even with modern software?