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Or just will allow me to use it?

I currently have 4gb and sometimes I run out of RAM.

Would SL per se consume more RAM?

It looks like I'm not running out of ram yet.

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You have 4GB of RAM and sometimes you run out? What the hell are you doing to that poor machine? – Telemachus Aug 27 '09 at 21:22
Also, what do you mean by "Or just will allow me to use it?" Use what? Your RAM? Snow Leopard? – Telemachus Aug 27 '09 at 21:23
I'm intrigued. I have 4GB of RAM, and uptime of over 2 months on my 3rd generations MacBook, run VM's all the time, and have yet to run out of RAM. OSX has one of the best memory management routines out there. – BinaryMisfit Aug 27 '09 at 21:31
Not much. Parallels running Oracle XE + an Eclipse based IDE :( I don't like that either. That was actually one of the arguments I gave to my boss to convince him ( :P ) I needed this MacBookPro. I use to have a Dell 6300 with 2 gb and I constantly run out of ram ( about every 2 hrs or so ) I told him "If I buy this Mac I won't have that problem anymore" And actually I don't. When that happens, I just shutdown FF, iTunes, and Chrome and get about 500 mb back again and I can keep working. – OscarRyz Aug 27 '09 at 21:55
Sounds like the OS isn't the problem, the apps are :-). Is VMware Fusion instead of Parallels an option? – jtimberman Aug 27 '09 at 22:09
up vote 4 down vote accepted

The main disadvantage of 64-bit architectures is that relative to 32-bit architectures the same data occupies more space in memory (due to swollen pointers and possibly other types and alignment padding). This increases the memory requirements of a given process and can have implications for efficient processor cache utilization. {source}

Or from Apple's own documentation:

Myth: My application will run much faster if it is a "native" 64-bit application. Fact: Some 64-bit executables may run more slowly on 64-bit Intel architectures because of increased cache pressure. {source}

Many core apps have been rewritten as 64bit. That means more memory will be needed by those apps overall. I can't see how Snow Leopard will use less memory than Leopard, unless apple have made some significant optimisations elsewhere (as MS did going from Vista > Win7).

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Noooooooohhhh!!!!! – OscarRyz Aug 27 '09 at 23:16
Oscar: perhaps optimisaions elsewhere will help for the apps you use. As an example, if you can run a 64bit kernel, the [double TLB swap][1] will be negated; I'm not saying SL will be measurably worse for you, it could be better. but it certainly wont use less RAM unless optimisations elsewhere overcome the 64bit overhead... [1]… – The Tentacle Aug 27 '09 at 23:32
I guess there is only one way to find out. I have ordered my copy already. Can't wait!! – OscarRyz Aug 27 '09 at 23:36
@The Tentacle: It seems that they might require more ram but also it will be used in a better way. The second link is pretty interesting. – OscarRyz Aug 28 '09 at 0:37

Since Snow Leopard is going to be the default on new machines as of Friday, and Apple makes machines with a lot less RAM than 4GB, I would assume that it will work just fine. Having said that, I don't have any machine with more than 2.4GB of RAM (various OS X and Debian machines), and I never hit a wall the way you say you do. So, maybe you're crunching numbers in a way that requires a lot of memory.

(Apple is making a big deal (and rightfully so) out of the fact that Snow Leopard takes up less space on your hard drive than Leopard, but this doesn't necessarily mean anything in terms of memory consumption.)

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Snow Leopard is all about optimization. Apple's goal is for everything to run faster on existing hardware. So, if anything, Snow Leopard will probably consume LESS RAM :)

Details here:

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Many of the core apps in Snow Leopard are 64bit - they have to consume more memory (64 > 32). You are trading efficiency vs. footprint... And a number of the first benchmarks (e.g. CNet) show Snow Leopard running slower than Leopard on existing apps. – The Tentacle Aug 27 '09 at 23:01
my first down-voted response :( i guess i shouldn't talk out my a** ;) – lo_fye Aug 28 '09 at 13:31

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