Partition size advice

[Bob Coxner]

I'm totally new to OS X. I want to add Bootcamp to my new MBA 13/4/128 but I don't have a good idea for the Windows partition size.

I've cleaned my ssd as much as possible and I have 105.92gb free. I don't plan on putting much on the Windows partition. Probably no more than 20gb (over and above Windows itself).

Suggestions?

 

[speacock]

It depends which version of Windows

A clean W7 install is about 5-7GB but can grow much bigger once you put on things like service packs, 15-20GB is not uncommon. XP on the other hand is much smaller - say 2-3GB or 7-8GB with SP. On top of this Windows will want 1.5x the amount of RAM you have for a pagefile; you can cut this right back if you wish but some applications may perform poorly or report memory errors.

Ideally you want to slipstream all the updates and fixes into your Windows build so that it is as small as possible (look up nLite for an easy way of doing this), that way you can keep the Windows build as small as possible, but you will spend time creating it.

You may be better off running Windows in a virtual machine rather than using Bootcamp, it's alot more flexible and much less costly in terms of disk space, what you spend on a copy of VMware fusion or similar you'll save in time and diskspace.

 

[Quad5Ny]

With 4GB of RAM Windows 7 x64 by default will use about 17.5GB*. If you Disable Virtual Memory (pagefile), Hibernation and System Restore you can drop that figure to about 10.5GB.

Remember you need space for Applications, Updates, Boot Camp drivers, Personal files, Internet browser cache, ect. So the minimum I would go with is 50GB (40GB if your tweaking).

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*(1GB = 1,073,741,824 bytes, but in OS X 1GB is reported as 1,000,000,000 bytes)

 

[Bob Coxner]

Sorry. I should have specified that I would be using Win 7 Pro. I hadn't really thought about whether to use 32 or 64. 32 bit is fine for my needs, if that's an option.

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You may be better off running Windows in a virtual machine rather than using Bootcamp, it's alot more flexible and much less costly in terms of disk space, what you spend on a copy of VMware fusion or similar you'll save in time and diskspace.

You gain space but lose power, right? My understanding is you have to divide your RAM between OS X and Parallels, for example. If you have Parallels installed, but you're not using it at the moment, is it tying up allocated RAM or is all of your RAM free for OS X? Or, is Parallels essentially running all the time and always requiring RAM?

 

[speacock]

Sorry. I should have specified that I would be using Win 7 Pro. I hadn't really thought about whether to use 32 or 64. 32 bit is fine for my needs, if that's an option.

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You gain space but lose power, right? My understanding is you have to divide your RAM between OS X and Parallels, for example. If you have Parallels installed, but you're not using it at the moment, is it tying up allocated RAM or is all of your RAM free for OS X? Or, is Parallels essentially running all the time and always requiring RAM?

The Windows OS running in the VM will be slower than running native and will definitely have less RAM available, but if the host system is reasonably powerful with sufficient RAM and if you're not trying to do anything too intensive then it won't feel slow. I run VMware fusion on a 2.4GHz C2D macbook and it performs perfectly acceptably running Windows XP in a VM. If you're running heavyweight processes that need lots of RAM and plenty of processing then you may feel the performance hit, but then if you're doing this the MBA running Windows 7 probably isn't the right platform for it anyway.

I can't speak for Parallels (though I'm pretty sure it's the same situation), but VMware Fusion uses no RAM or processor resources (or at least only a tiny bit for the kernel level stuff like virtual network adapters) when it isn't running. It's just like any other application in that you start it, run up your Windows (or other OS) VM and then shut it down when you're finished. So you only lose RAM while Fusion or Parallels is running, not when it's idle, like any other application it must yield resources if demanded by the OS, so it can be paged out and forced to yield the processor if the OS decides it needs them for other purposes.

The question of 64 or 32 bit Windows will ultimately come down to how much RAM you have and whether you have any incompatible applications. If you have 4GB or less or RAM then 64 bit is pretty pointless. If you have more then Windows can use it, but you may have problems with application compatibility, just as occurs under Mac OS X 64 bit - it's rare but it can happen. I run Windows 7 x64 on one of my Windows desktops and am yet to have an application not work under it, but I know it's possible.