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When reinstalling Windows 7, does the language, version, architecture (64-bit or 32-bit) or source (OEM, retail, or MSDN) matter?

I'm about to reinstall my copy of Windows 7.

The DVD comes with 32bit and 64bit versions.

I originally installed the 32bit version and have activated it.

What I can't seem to find out from anywhere is whether I can reinstall it but use the 64bit version and will the activation still be valid? Or do I have to buy a whole new copy of Windows 7?

Also I think there are 64bit drivers for all the devices I'm using, but are there any major applications that have problems in 64bit?

Finally, is the difference between 32 and 64bit that noticable in day to day use? (Assuming I upgrade my RAM to say 8gb - currently 4gb).

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migrated from Nov 13 '10 at 13:56

This question came from our site for professional and enthusiast programmers.

marked as duplicate by nhinkle Jun 28 '11 at 1:05

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

This question should be asked in – plaes Nov 13 '10 at 13:39

The licence keys are the same for 32bit and 64 bit versions of the same edition (Home Premium, Professional, ...) of Windows 7. You only need the 64 bit installation media. You cannot upgrade between them, only perform a new installation, so backup your data.

The speed advantage of 64bit is usually neglible, the important advantage is that you can use 4GB or more RAM. 8 Gigabytes will most likely not result in a noticeable performance increase for standard usage, compared to 4 Gigabytes. If you use a lot of memory-intensive applications like virtualization, image manipulation, etc. there are very real benefits to putting more RAM into your computer.

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Well, 64 bit Windows could offer a speed increase when running 64 bit native applications (most of the applications nowadays are still 32 bit), since they can take advantage of the large number or CPU registers and 64 bit operations. Of course, this will be only noticeably in CPU intensive operations like compression. – Alberto Martinez Nov 13 '10 at 23:25

Also I think there are 64bit drivers for all the devices I'm using, but are there any major applications that have problems in 64bit?

Yes, a few apps will have problems but not many.

When I first got my 64bit machine, the Cisco VPN software (32bit) supplied by my company didn't work. I had to wait for the 64bit version, before I could access the company server from home. Since then, I haven't had a problem but I always install the 64bit version of apps if they are available.

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VPN software is a special case for software because it normally also includes a network driver that it has to load. So in that case the VPN software is probably fine on 64-bit but they only included a 32-bit network driver. – GAThrawn Dec 2 '10 at 12:53

If your DVD comes with both 32bit and 64bit, the key will work on both copies - Microsoft wouldn't give you dud software now?

EDIT: just read the rest of your question. using 64bit will offer some speed advantages, as well as being able to store much larger numbers.

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cough Vista cough – Ignacio Vazquez-Abrams Nov 13 '10 at 13:40
@Ignacio - cough pretty much every M$ product, IMO cough ;-P – Bojangles Nov 13 '10 at 13:41
cough putting a dollar sign in the acronym MS does not make you look clever cough – oKtosiTe Dec 2 '10 at 12:04

are there any major applications that have problems in 64bit?

A search should reveal any major problems, but the 64 bit OS should run 32 bit programs without any problems.

See this question on the gaming site about the game Crysis. The OP experienced problems with the 64 bit version of the program which went away when he installed the 32 bit version.

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