Go Back   MacRumors Forums > Apple Hardware > Desktops > iMac

Reply
 
Thread Tools Search this Thread Display Modes
Old Feb 14, 2013, 03:39 AM   #26
Nuke61
macrumors 6502
 
Join Date: Jan 2013
Location: Columbia, SC
Quote:
Originally Posted by crows View Post
Since you can get 32GB for about $170 why not just get the 32GB, like some one else said if you do any VM's it will help you greatly to have so much free ram to assign for the vm. Just use your iMac when you get it and if you feel it needs more RAM after the test then upgrade, if not you can just wait and ram will get cheaper over time.
I completely agree with getting more ram, but I don't undertand the position of getting more ram to use in a VM. If you allocate 4 GB of ram to a VM, that means you'll have a longer store/restore for that VM. If you only allocate 1 GB of ram to that VM, it's a much quicker store/restore. If a *real* computer runs out of ram, it then goes to virtual memory, which is typically much slower than ram. But in the case of a VM, when it runs out of "real" ram, the "virtual memory" is still real ram, since the then entire VM is running in computer memory -- including the virtual hard drive.

Maybe I'm just not seeing it, but I don't see the benefit to allocating more of the Mac memory to the support of a VM with more memory. Maybe I'm just misunderstanding how it works, and if so, feel free to educate me.
Nuke61 is offline   1 Reply With Quote
Old Feb 14, 2013, 03:41 AM   #27
Brian Y
macrumors 68020
 
Join Date: Oct 2012
Quote:
Originally Posted by Jonathan20022 View Post
You'll be satisfied with the 8 trust me, if you feel like you need to expand on it. I'd say either add another 8gb, or 16gb.

32 is a bit overkill, from someone who edits videos and does heavy gaming on my own computers. I never exceed 10 or 12 at most pushing my computer, at this point 32gb is just a bragging point. There's almost no one out there that even reaches that amount in use actively and if someone here does I'd like some proof at the very least.

You'll be okay with one of the smaller upgrades trust me.
I have 32GB in my 2011 iMac and I've had 30GB used before now. I do lots of testing in various virtual machines.

And whilst you might not *need* 32GB, it means the difference between allocating 4GB of RAM to each VM instead of 2 (I usually have about 6-7 running). And in a virtual machine, 2-4GB makes the world of difference. For what it costs for 32GB these days - IMO it's a no brainer if you do any kind of virtualisation.

----------

Quote:
Originally Posted by Nuke61 View Post
I completely agree with getting more ram, but I don't undertand the position of getting more ram to use in a VM. If you allocate 4 GB of ram to a VM, that means you'll have a longer store/restore for that VM. If you only allocate 1 GB of ram to that VM, it's a much quicker store/restore. If a *real* computer runs out of ram, it then goes to virtual memory, which is typically much slower than ram. But in the case of a VM, when it runs out of "real" ram, the "virtual memory" is still real ram, since the then entire VM is running in computer memory -- including the virtual hard drive.

Maybe I'm just not seeing it, but I don't see the benefit to allocating more of the Mac memory to the support of a VM with more memory. Maybe I'm just misunderstanding how it works, and if so, feel free to educate me.
That's not how it works. It's down to the guest OS to handle virtual memory - and it does so within it's own virtual disk - it cannot use extra RAM from the host.
Brian Y is online now   1 Reply With Quote
Old Feb 14, 2013, 05:52 AM   #28
crows
macrumors member
 
Join Date: Nov 2012
Quote:
Originally Posted by Nuke61 View Post
I completely agree with getting more ram, but I don't undertand the position of getting more ram to use in a VM. If you allocate 4 GB of ram to a VM, that means you'll have a longer store/restore for that VM. If you only allocate 1 GB of ram to that VM, it's a much quicker store/restore. If a *real* computer runs out of ram, it then goes to virtual memory, which is typically much slower than ram. But in the case of a VM, when it runs out of "real" ram, the "virtual memory" is still real ram, since the then entire VM is running in computer memory -- including the virtual hard drive.

Maybe I'm just not seeing it, but I don't see the benefit to allocating more of the Mac memory to the support of a VM with more memory. Maybe I'm just misunderstanding how it works, and if so, feel free to educate me.
Not the case on what I've used, at least on vmware it has a virtual disk which is a file on your hard drive that's where the VM stores and reads files from and if it runs out of ram it uses that as the virtual memory space on the virtual disk so the VM would get pretty slow at that point. It may have some feature where if the vm is running out of memory it would use other available free RAM if you have any, but then it would take more from OS X. I'm sure the entire VM is not running on memory if you had a 100GB virtual disk it would need 100+GB of RAM to load the entire thing to memory, that's not how it works.
crows is offline   0 Reply With Quote
Old Feb 14, 2013, 08:05 AM   #29
kennyap
macrumors regular
 
Join Date: Jul 2012
Location: Cayman Islands
Quote:
Originally Posted by gaddster View Post
Lots of great responses here, love the 'page out' ones although I dont have a clue what that means

I dabble with after effects from time to time so I can see where the extra Ram would benefit there.

I think buying the crucial ram at 148 will at least ensure I dont buy anymore ram for a for years
Good decision. The point being that if you'll be intensively using your nice new expensive computer, then maxing out the ram is sound advice. Skimping on ram makes little sense to me when you consider cost vs. benefit.

Yes everyone could make do with 8GB of ram, including myself, but the computer will be slower.
__________________
iMac 27" 3.4ghz 680mx 840 Pro SSD 512gb
2012 13" rMBP | 2011 27" Imac 3.5ghz 2gb vram
2011 MBP 17" | 2011 MBA 11" & 13"
kennyap is offline   0 Reply With Quote
Old Feb 14, 2013, 08:08 AM   #30
RichiMac
macrumors member
 
Join Date: Dec 2012
Location: SoCal
Ram used to cost what an entire computer costs these days. Its relatively cheap (if you don't buy it from Apple). And too much?? Not for long! I just replaced my venerable Dell 8400 with this new iMac 27. I had maxed the Dell out with 4 gigs of ram! OOOO!. That was a lot back then. I remember when 1 gig of ram got you bragging rights.

The point is...ram is cheap and eventually you will need it. They keep adding complexity to programing, at least in the amount of data used. I bought mine from Crucial, threw it in and I am good to go until I need to replace my ancient 2012 iMac some day...when they will be saying "are you serious! You only had 32 gig of ram! Wow, how did you even manage to fire that dinosaur up?"
__________________
3.4GHz Quad-Core Intel Core i7, 32GB 1600MHz DDR3 SDRAM-4X8GB, 3TB Fusion Drive, NVIDIA GTX 680MX, MAGIC TRACKPAD
RichiMac is offline   0 Reply With Quote
Old Feb 14, 2013, 08:15 AM   #31
dma550
macrumors 6502
 
Join Date: Sep 2009
Location: CT
I always max except on dedicated servers that have fixed duties, or where RAM replacement is cheap.

I have two VM's running now, one with 6gb (Windows 2008 server, SQL server and some dev tools) and a 4gb Customer VM. This memory is wired (pinned) and unusable by the host. This can at times force my mac to go into contention for RAM and become slow/non responsive. You may not need this, but having a well of RAM to draw from means smoothness and no swapping.
dma550 is offline   0 Reply With Quote
Old Feb 14, 2013, 08:33 AM   #32
kennyap
macrumors regular
 
Join Date: Jul 2012
Location: Cayman Islands
Quote:
Originally Posted by Nuke61 View Post
I completely agree with getting more ram, but I don't undertand the position of getting more ram to use in a VM. If you allocate 4 GB of ram to a VM, that means you'll have a longer store/restore for that VM. If you only allocate 1 GB of ram to that VM, it's a much quicker store/restore. If a *real* computer runs out of ram, it then goes to virtual memory, which is typically much slower than ram. But in the case of a VM, when it runs out of "real" ram, the "virtual memory" is still real ram, since the then entire VM is running in computer memory -- including the virtual hard drive.

Maybe I'm just not seeing it, but I don't see the benefit to allocating more of the Mac memory to the support of a VM with more memory. Maybe I'm just misunderstanding how it works, and if so, feel free to educate me.
The vm's (virtual) hard drive is contained within the Host's hard drive space (not RAM memory). I use Fusion and ESXi and can tell you vm speed is very dependent on amount of allocated RAM, in most cases much more so than allocated processors.

----------

Quote:
Originally Posted by RichiMac View Post
I just replaced my venerable Dell 8400 with this new iMac 27. I had maxed the Dell out with 4 gigs of ram! OOOO!. That was a lot back then. I remember when 1 gig of ram got you bragging rights.
I remember buying 8MB (Megabytes) of RAM for $276.99 to bring my brand new Dell Pentium Pro up to the maximum 16MB. I was so proud
__________________
iMac 27" 3.4ghz 680mx 840 Pro SSD 512gb
2012 13" rMBP | 2011 27" Imac 3.5ghz 2gb vram
2011 MBP 17" | 2011 MBA 11" & 13"
kennyap is offline   0 Reply With Quote
Old Feb 14, 2013, 09:44 AM   #33
Jonathan20022
macrumors newbie
 
Join Date: Feb 2013
Quote:
Originally Posted by 12dylan34 View Post
You knew that there would be that one guy... After Effects is using about 22 of my 32 at the moment.

Really though, I could live with 16. It's just a matter of being able to have more frames cached at any given moment.
"That guy", ha. I seriously doubt less than 5% of users on Computers exceed that amount, even at that point you're still only using 22gb out of the 32gb. Point is for what he needs, 32 is definitely a bit of overkill and that's how I see it. It's not like he's locked down, he can always expand on it later on.

He's going to be using Premier Pro, I'm pretty sure that if he got his iMac and felt like it was slowing down. He could easily just get either another 8, or 16gb worth of RAM. I'm just being realistic, he should get the amount of RAM he needs, I just spent 2500$ on my current iMac and throwing down another 200$ isn't something I can do at the moment. I have enough RAM lying around in my shop anyways, so I don't actually need to buy more RAM.

Quote:
Originally Posted by Brian Y View Post
I have 32GB in my 2011 iMac and I've had 30GB used before now. I do lots of testing in various virtual machines.

And whilst you might not *need* 32GB, it means the difference between allocating 4GB of RAM to each VM instead of 2 (I usually have about 6-7 running). And in a virtual machine, 2-4GB makes the world of difference. For what it costs for 32GB these days - IMO it's a no brainer if you do any kind of virtualization*.[COLOR="#808080"]
I can definitely see how you need it, but he definitely isn't doing that from what he's indicated.
Jonathan20022 is offline   0 Reply With Quote

Reply
MacRumors Forums > Apple Hardware > Desktops > iMac

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Similar Threads
thread Thread Starter Forum Replies Last Post
last minute decision; 21''/3.1Ghz i7/ 16gb RAM/ 512 flash. Do I need 32gb RAM 27''? bluesnina iMac 10 Feb 10, 2014 07:57 PM
2011 MP 2.2 i7 16 gb ram vs 2012 iMac 2.9 i5 32gb ram absoluteelsewhe iMac 3 Feb 8, 2014 04:03 PM
32GB RAM and no high ram usage tasks iMacLate2013 iMac 5 Jan 25, 2014 09:19 AM
32GB ram G5 quad rabidz7 PowerPC Macs 9 Dec 27, 2012 08:04 PM
Swap still being used even though I have 32GB of ram macmee OS X 3 Dec 21, 2012 12:45 PM

Forum Jump

All times are GMT -5. The time now is 09:11 PM.

Mac Rumors | Mac | iPhone | iPhone Game Reviews | iPhone Apps

Mobile Version | Fixed | Fluid | Fluid HD
Copyright 2002-2013, MacRumors.com, LLC