32 bit vs 64 bit Comparison

[zzz2496]

The fact is that the /3G switch won't change how many system memory can be addressed/accounted for globally.

Yes by defining /3G at system start up will increase the user space memory from 2 GB to 3 GB. But don't forget that this "user-mode virtual address space" is using the "global pool" of RAM that is addressable by the kernel. It still remains that the limit of memory you can "have" on a 32bit OS is still around 3GB. Depending on how many devices you have on your system, addressable memory count will go down along with increased device installed and vice versa.

Lordbob75, I think you should include our little chat over PM to the main thread. It will clear a lot of confusions.

zzz2496.

 

[Lordbob75]

I see... OK, wipe the slate clean. Let's go back to basics... I think I lead you to the wrong idea, I'll explain it in numbers this time...

Every device in our computer needs to have an address. The addresses for those devices are defined in hexadecimal format: 0x00000000 up to 0xFFFFFFFF in 32bit system (16^8 = 2^32). For a computer to be able to use a device, first it needs to make sure it's known - by giving it an address number (a 0xYYYYZZZZ number). This number is not related to your RAM, it's an independent value.

32bits processors understands 4.294.967.296 addresses: 0x00000000 up to 0xFFFFFFFF (2^32). This is the max for 32bit systems. Now let's say your have 4GB of RAM, you need to address every byte of it, which will require 4.294.967.296 addresses, this can't be, because the limit is 0xFFFFFFFF (4.294.967.296 in hexadecimal), so the system will reserve every device it found in your system on the lower part of the address space thus will abandon your RAM in the process. Let's say your devices use 0x00000000 to 0x2FFFFFFF (1.073.741.824) addresses.
Your RAM's address will have to start at 0x30000000 up to 0xFFFFFFFF (3.489.660.927 addressable RAM - RAM is calculated in bytes, thus 3.489.660.927 bytes). If you have 4.294.967.296 worth of RAM, your processor can't address the rest of your RAM (805.306.369 bytes), because it ran out of 32bit address space.

In 64bit systems you can have as much as 0x0000000000000000 up to 0xFFFFFFFFFFFFFFFF or 18.446.744.073.709.551.616 addresses, this is exactly 4.294.967.296 TIMES LARGER address space than 32bit systems (2^64). Let's say your devices uses 0x0000000000000000 up to 0x000000002FFFFFFF (which is 1.073.741.822 addresses), that will leave 18.446.744.072.635.809.794 addresses to use... Your devices addresses ends at 0x000000002FFFFFFF, your RAM will start at 0x0000000030000000 address ends at 0x0000000130000000. As you can see, the address space in 64bit processor still leaves a lot of room to expand.

I hope this clears the address reservation issue...

zzz2496

Hope this helps.

~Lordbob

 

[chinnu]

Haiii...need help

Hai.. i am using 64bit... when i installed oracle 10g in windows7 home premium i was unable to find odbc drivers.... when i changed the target path to 32 bit i was able tofind th drivers...when ever i try to connect to oracle using java its showing SQLException... can u plz get me out of this problem...

 

[alfranatic]

Very usefull article,for which thanks.

Now i do have a question.(i hope this wasn't asked already,if so i do apologize)

How about OEM licenses,i do have an installation dvd with only (??) the 64 bit edition.
Now could i use the same key to install a 32bit version???
I build my pc myself,hence the oem-systembuilder license,which is also a lot cheaper (+- 50%)

It's just something i would like to know,i defenitly will stick to the much superiour 64bit-version of win 7,but a lot of people asked me this???

I hope you or someone else might know.
Thanks in advance

 

[Lordbob75]

Very usefull article,for which thanks.

Now i do have a question.(i hope this wasn't asked already,if so i do apologize)

How about OEM licenses,i do have an installation dvd with only (??) the 64 bit edition.
Now could i use the same key to install a 32bit version???
I build my pc myself,hence the oem-systembuilder license,which is also a lot cheaper (+- 50%)

It's just something i would like to know,i defenitly will stick to the much superiour 64bit-version of win 7,but a lot of people asked me this???

I hope you or someone else might know.
Thanks in advance

You're welcome. The license key will work for both x32 and x64 versions. The restriction is on the version of Windows, such as Home Premium, Pro, and Ultimate.

~Lordbob

 

[alfranatic]

Thanks,Lordbob for your swift and clear answer.

 

[Lordbob75]

Thanks,Lordbob for your swift and clear answer.

No problem. Glad to help.

~Lordbob

 

[blondie91702]

This is great info! My system came pre-installed by Best Buy Geek squad ... does that mean, if I wanted to, I could reformat and choose to use x32? Also, did not see anything about the x86 ... I have two sets of program files it seems... one says Programs x86 ?

 

[Lordbob75]

This is great info! My system came pre-installed by Best Buy Geek squad ... does that mean, if I wanted to, I could reformat and choose to use x32? Also, did not see anything about the x86 ... I have two sets of program files it seems... one says Programs x86 ?

Ugh, Geek Squad...

Yes, you can install either x32 or x64 with the same key, as long as it is the same version (ie Home Premium, Pro, Ultimate).
Also, the Program Files x86 is the directory most programs will install to if they are not native x64, and this is perfectly normal.

~Lordbob

 

[blondie91702]

Thank you !!

 

[Golden]

That's a well written articel LordBob. Something that I never understood, is what are the effects if any, of installing a 64bit OS onto a 32bit PC?

 

[Lordbob75]

That's a well written articel LordBob. Something that I never understood, is what are the effects if any, of installing a 64bit OS onto a 32bit PC?

What do you mean by 32 bit PC? They haven't made (for consumer computers) pure 32 bit processors for years...

~Lordbob

 

[Golden]

Thanks LordBob. I was under the impression that there were still 32bit processors out there, but it seems I was wrong. Thanks again for a good article.

 

[zzz2496]

Little notes:

x64 = x86_64, meaning Intel's x86 based processor with AMD's 64bit extensions. x64 is a shorthand of x86_64.
x86 = x86, meaning vanilla Intel's x86 based processor.

The "x" is referring to Intel's whole long line of many *86 processors, starting from 8086, 80286, 80386 (and of course 80387 math-co processor), 80486 (and 80487 math-co processor), Intel Pentium series (80586 with integrated math-co processor and MMX), and many more. They all have *86 number, thus the x86.

There is no x32. The correct term to refer to the 32bit is "x86". So if you find any software of any kind that is written with x86 (not x86_64) on it, it's 32bit software.

zzz2496

 

[Golden]

Little notes:

There is no x32. The correct term to refer to the 32bit is "x86". So if you find any software of any kind that is written with x86 (not x86_64) on it, it's 32bit software.

zzz2496

Excellent! Very informative. +1

 

[Keiichi25]

Well, another point is that most programs written for Windows XP are normally 32 bit OS written. It wasn't until Vista and Win 7 that the normal user started seeing x64. There is Windows XP x64, but it wasn't really well supported and only other systems that actually started using x64 bit processing was Windows 2003 and above server level when Servers started needing more and more memory access. But again, there wasn't a lot of x64 based applications or software.

Windows Vista and Windows 7 32-bit is out there for people with some older systems that don't support larger memory addressing. While the processor might support 64 bit processing, the better use of x64 is when you can do more than 4 gigs of RAM and having programs that will actually use 64-bit processing needs, usually heavy number crunching based programs like Adobe Photoshop or rendering based programs that will need larger memory spaces and number crunching.

 

[Lordbob75]

Well, another point is that most programs written for Windows XP are normally 32 bit OS written. It wasn't until Vista and Win 7 that the normal user started seeing x64. There is Windows XP x64, but it wasn't really well supported and only other systems that actually started using x64 bit processing was Windows 2003 and above server level when Servers started needing more and more memory access. But again, there wasn't a lot of x64 based applications or software.

Windows Vista and Windows 7 32-bit is out there for people with some older systems that don't support larger memory addressing. While the processor might support 64 bit processing, the better use of x64 is when you can do more than 4 gigs of RAM and having programs that will actually use 64-bit processing needs, usually heavy number crunching based programs like Adobe Photoshop or rendering based programs that will need larger memory spaces and number crunching.

While this is true, modern x64 bit systems support x86 programs (except in rare cases) just fine.

Though I would love to see pure x64 programs (and OS), that just won't happen while MS is writing with backwards compatibility.

~Lordbob

 

[zzz2496]

Where does this "x32" comes from ??? Lordbob, can we stop using "x32"? There is no "x32" term. x64 term comes from a shorthand form of x86_64 (meaning x86 instructions with AMD's 64 bit extensions). There is no x86_32 ever...

And there are no 80x32 processors on Intel's catalog that I'm aware of... We should use the correct terminology at all times. It's better that way...

zzz2496

 

[Lordbob75]

Where does this "x32" comes from ??? Lordbob, can we stop using "x32"? There is no "x32" term. x64 term comes from a shorthand form of x86_64 (meaning x86 instructions with AMD's 64 bit extensions). There is no x86_32 ever...

And there are no 80x32 processors on Intel's catalog that I'm aware of... We should use the correct terminology at all times. It's better that way...

zzz2496

The x32 came from 32bit...?

I am more confused about where x86 came from.

However, will do.

~Lordbob

 

[minimeister]

Has anyone failed to notice that MS doesn't really support 64-bit OS? Windows update site only runs on 32-bit, the only reason to have 32bit IE installed by default so you can do updates? Give me a break. If MS is not going to support it, why in the world would you ever get it?