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I see laptops being sold with as little as 2gb of RAM yet with a 64bit operating systems (Windows7). I cant see the advantages nor reasoning behind this. Discuss.

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Do they say it's 64bit? Windows 7 is available in 32-bit versions as well. – Macha Jan 3 '10 at 16:40

This is a QA site not a discussion site, so discussing it isn't going to happen.

There are certain advantages to using a 64 bit OS aside from being able to address more memory, for example:

  • Some operating systems reserve portions of process address space for OS use, effectively reducing the total address space available for mapping memory for user programs. For instance, Windows XP DLLs and other user mode OS components are mapped into each process's address space, leaving only 2 to 3 GB (depending on the settings) address space available. This limit is currently much higher on 64-bit operating systems and does not realistically restrict memory usage.

  • Memory-mapped files are becoming more difficult to implement in 32-bit architectures, especially due to the introduction of relatively cheap recordable DVD technology. A 4 GB file is no longer uncommon, and such large files cannot be memory mapped easily to 32-bit architectures; only a region of the file can be mapped into the address space, and to access such a file by memory mapping, those regions will have to be mapped into and out of the address space as needed. This is a problem, as memory mapping remains one of the most efficient disk-to-memory methods, when properly implemented by the OS.

  • Some programs such as data encryption software can benefit greatly from 64-bit registers (if the software is 64-bit compiled) and effectively execute 3 to 5 times faster on 64-bit than on 32-bit.

  • Some complex numerical analysis algorithms are limited in their precision by the errors that can creep in because not all floating point numbers can be accurately represented with a small number of bits. Creeping inaccuracies can lead to incorrect results, often leading to attempts to divide by zero, or to not identify two quantities as being identical for practical purposes. International Computers Limited added 128-bit support to the ICL 2900 Series in 1974 largely as a result of requests from the scientific community.


Also, these days there aren't really many issues with a 64 bit OS unlike the old days, when driver compatibility etc. was a big problem.

One other possible reason they might decide to sell a machine with a 64 bit OS is, for example, if they offer various different options on the laptop, for example a 2GB of RAM version and a 4GB of RAM version, it's easier to just load the same software on both than separate OS's per model.

More here:

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The main advantage is that you can put in another couple of GB, and use all of it, without having to reinstall the OS - which is a lot of time and effort. It gives you future expansion possibilities that a 32bit OS doesn't.

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+1 that's pretty much the only reason i can see. – Molly7244 Jan 3 '10 at 16:09
There are many more reasons than just this, to use a 64 bit OS. – Michael B. Jan 3 '10 at 17:13
yep, exactly as many reasons as there are programs that explicitely require a 64-bit OS of course :) – Molly7244 Jan 3 '10 at 20:32

You can install 64 bit OS with 2GB ram. There just isn't much point to doing so.

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There are other reasons to use a 64-bit OS than access to RAM. Read through this comparison of a system with 32-bit OS vs. 64-bit OS:… – casualuser Jan 3 '10 at 19:59
Answer is perfectly acceptable, although a bit outdated. Three years ago this would have been right on the money +1. I don't believe in downvotes for incorrect answers as long as they aren't spam. – Moshe Jan 4 '10 at 3:20
Yes. That is true. Certain tasks will run faster using 64 bit processes however, some will not be faster, in fact, some tasks will run slower. Personally, I would go with 64 bit, but if you need to run older software, or use older hardware, the drivers/software may not work in 64 bit operating systems. – benjamin239 Jan 5 '10 at 15:38

The main advantage is that the manufacturer doesn't have to support any 32 bit systems. It's one less configuration for them to track, support, update drivers for. I've noticed a lot of the consumer systems from HP/Dell, etc. are only available with 64 bit Windows.

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Very simply: a 64 bit OS is very rarely slower, uses very little more RAM, and is often significantly faster. Mostly this is because x86_64 has many more registers than x86, and therefore the compiler has a much easier job optimising code. Often the code gets smaller. Combine that with the advantages of 64 bit addressing, and you get a better system as a result. The only cost is that sometimes you might not be able to find a driver for some old or exotic hardware.

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