Can this work, Can I do with less?

what exactly are you doing with the VM's? it all depends on how much resources you give them. 3 VM's at once with 8gb of ram is definitely pushing it though.

Can you run 3-4 VM's and native apps? Yes. I would go 4-core/16GB RAM no doubt. I wouldn't use an Air. It might work though, depends on how demanding your VM's are. They just seem to run browsers so, possibly it would work.

Number of displays? This article indicates that Air can support 2 external montiors, the Pro can support 3 externals in addition to the retina LCD.

The Retina MacBook Pro, on the other hand, sports two physical Thunderbolt ports plus an HDMI port, meaning that you don't need to do any daisy-chaining to get to the maximum of four displays that the more powerful NVIDIA GeForce GT 650M is capable of pushing.

http://arstechnica.com/apple/2012/06/new-macbooks-can-manage-many-many-monitors/

If you really want the Air I might consider toning down your requirements? Why so many monitors and VM's? One big 27" display can simultaneously open a lot of browser windows.

Maybe you buy an Air and try it for a few weeks, return it if it doesn't suit your needs. That's what the trial period is for. You use-case is rather unique and demanding, I think this is the best way.

less is better sometimes

You can do it with less. When developing a couple of web apps I originally bought a Win7 6-core PC with 8GB RAM. I ran 2-3 VM's. They were Linux web server & db server plus an XP desktop to test browsers. It was if anything overkill. I did this with two monitors. I got tired of the PC though.

I switched to a Macbook Pro 2011 i7 with 16GB RAM and SSD, it performs as well or better than the PC. This with a single 23" 1080p monitor and the standard 1440x900 Macbook display. So you will be fine, no need even for the Retina unless you have an extra $1000 laying around

Maybe with windows VM's there's more overhead I don't know. The Linux servers are easy to spawn a bunch of VM's because they are mostly not doing anything.

InlawBiker said:

Maybe with windows VM's there's more overhead I don't know. The Linux servers are easy to spawn a bunch of VM's because they are mostly not doing anything.

Click to expand...

Windows VMs have significantly more overhead. You'd be lucky if your fan doesn't complain the entire time. And that's to say nothing of RAM usage or anything else.

In fact, if it's to run 2 - 3 Windows VMs concurrently, and at least one of them is Windows 7, then 16GB of RAM is definitely not enough, and you want an octo-core CPU.

swordsmn said:

Bill,

I appreciate your comment. You have my attention.
I do believe my developers run at least 2 Win vm's often using vmware 9.
Frankly I don't think many have anything approaching 16 gig on their win ? Host. The ol company is not maxing out their occasionally dated hardware either, so I'm confused. I will ask around tomm.

Perhaps you're assuming my app is a bigger hog than it is. My IT guy is the one who warned me Win 8 IS going to need 2 gig min and I can't believe 2008 R2 wouldn't want that or more... But 16 gig inadequate? Ok but i gotta do more research.

I may not need to run 2+ win vm's when not actively researching something but I sure don't want to burn up the ol pc either if i need that environ an hr or 3 daily.

Again, I'm not rendering graphics here, editing video or audio or ultra gaming... I'll have a server with sql2008, idling most times with 1-2 of my apps exe services running - waiting for a client to request a file and some program comments/info. Clients re-login as needed too. Over a tcp/udp port. These things sit most times.
Does that mitigate any of the 8 core requirements etc.

I just don't wanna believe I need a "cray" to get this done... I will though refrain from trying to drive 4 monitors as I alluded to in my op.
Let's say: tbolt display plus 1 ( either the retina or one of those dvi 20" screens)

Click to expand...

I was assuming you were planning on doing something serious in those VMs... that you'd need Windows.

And unfortunately, running SQL databases do fall into the "serious" category even though you may think it shouldn't.

Let me take it slowly from point to point:

VMs take up a fixed amount of RAM on your computer. It's not dynamically allocated (at least neither VMWare nor Parallels does that from my experience). So once you assign RAM to a VM, and you run the VM, that RAM is gone. For instance, if you assign 4GB RAM to a Win 7 VM, and 4GB to a Win 8 VM, then run them both at the same time, then you absolutely need to have more than 8GB of RAM free (as in... not used by something else). Add in another Windows VM with 4GB RAM and you're looking at something close to 12GB of total used RAM not even counting RAM used by OSX... so now suddenly 16GB doesn't seem so plentiful anymore.

Of course, you can economize and run each VM with the bare minimum 2GB RAM... and it'll run just fine. But if you have sufficiently big SQL databases with some big tables, then it's actually better to give it as much RAM as you possibly can so that it doesn't thrash your storage or kill CPU cycles. Here's a good article on why this is the case:

http://sqlnerd.blogspot.com/2006/07/memory-use-in-sql-server.html

Last but not least, I mentioned RAM used by OSX. This is actually also quite a concern after OSX Lion as new features introduced by Apple have yet to be solidified. What I mean is that... they still have small bugs here and there. Especially with regard to Safari, which you mentioned, as Safari has some memory leaks that will cause RAM usage to skyrocket.

And just as an aside, if you plan on getting a Retina MacBook, then they will use up more RAM than traditional computers. Why? Because the Retina graphics assets they load for the sharper interface take up 4x more RAM space. It doesn't mean Retina MacBooks use 4x more RAM than normal computers, since there are things stored in RAM that aren't graphics assets... but for what it's worth, the increase in RAM usage is still noticeably higher than for traditional computers. That's why all Retina MacBooks come default with 8GB RAM rather than 4GB.

So I guess I "exaggerated" the need for 16GB of RAM... but at the same time, I think it's still worth mentioning, especially since you plan on running 2-3 VMs at the same time.

Also, the octo-core suggestion was just to keep things responsive. Each VM will need its own processor to keep from "misbehaving" and cause the entire system to crash. With a quad-core CPU, 3 VMs will reduce your usable CPU core down to 1. Running 1 CPU core, while okay in general, is not a good idea.