[Mephisto]

Understanding the true difference between 64 and 32 bit
Understanding the true difference between 64 and 32 bit
Two very informative articles exposing the pros and cons of 32-bit and 64-bit Windows OSs.

Which Vista Edition is Right for me? (Basic/Premium/Business/Ultimate)
A great article going through the features of every version of Vista. Very useful for those trying to decide what version is right for them.

[Tweak] The Vista Forums OEM Pack
Cool tweak to install onto friend's or customer's computer to advertise the site.




Created on September 30^th, 2008

[LMiller7]

The comparisons of 32 and 64 bit system are very good but miss an important point.
Probably the #1 advantage of a 64 bit OS is the vastly larger virtual address space available, but only when running native 64 bit applications. Note: this is the virtual address space and is completely independent of how much RAM is in the system.

All modern versions of Windows are based on virtual memory. In fact, the last version that did not use such a system was Windows 3.1, released in 1992. In these systems all access to memory is virtualized, direct access to physical RAM is impossible. 32 bit applications are provided with a virtual address space of 4GB, the lower 2GB being private to each process, while the upper 2GB is common to all processes and is used by the system. Note: the 2GB process address space is private and not shared with other processes. A process cannot even see the address space of other proceses, let alone write to it. Once again, this is a virtual address space and is totally independent of RAM size. The system assigns RAM to each address space as needed in a way that is totally transparent to applications. Applications have only a limited influence on this process.

All of an applications code and data, plus all DLL's accessed, must fit within it's 2GB address space. For some large applications (image and video editing, databases, and games) this can be a tight squeeze. And there are further complications. In many cases DLL's must be loaded to specific addresses, resulting in the address space being broken up into a number of smaller pieces. An application request for a large block of contiguous memory may fail, even when the total space is adequate.

Adding more RAM, even beyond 4GB when possible, does not help. The problem is a limited virtual space, not RAM. Most systems allow changing the address space division to allow 3GB for applications and 1GB for the system but this offers only limited relief. This is available only to applications that have explicitly indicated that they are compatible. Most aren't. There is a special technique available to applications but it has severe limitations and is not a real solution.

The real solution is to be found in a 64 bit OS. 64 bit Vista provides an 8 terabyte private address space for each 64 bit application. That is 4096 times the limit in 32 bit systems! The system address space is expanded to similar levels, leading to more efficient caching and avoiding a number of issues that sometimes occur. And the system need not have a great deal of RAM for applications to enjoy these benefits either. A 64 bit processor could theoretically offer an even greater space than that but there are practical issues to take into account.

But this advantage is primarily for 64 bit applications. 32 bit applications that are large address aware will receive a 4GB private address space. All others (the majority) will see no advantages, aside from the limited performance benefits.

Conclusion:
The larger virtual address space is the prime advantage of a 64 bit OS, although at present few applications can benefit from it. Just about everything alse can be had in a 32 bit OS.

[mhodge33]

LMiller7, on Jul 7 2009, 05:16 PM, said:

The comparisons of 32 and 64 bit system are very good but miss an important point.
Probably the #1 advantage of a 64 bit OS is the vastly larger virtual address space available, but only when running native 64 bit applications. Note: this is the virtual address space and is completely independent of how much RAM is in the system.

All modern versions of Windows are based on virtual memory. In fact, the last version that did not use such a system was Windows 3.1, released in 1992. In these systems all access to memory is virtualized, direct access to physical RAM is impossible. 32 bit applications are provided with a virtual address space of 4GB, the lower 2GB being private to each process, while the upper 2GB is common to all processes and is used by the system. Note: the 2GB process address space is private and not shared with other processes. A process cannot even see the address space of other proceses, let alone write to it. Once again, this is a virtual address space and is totally independent of RAM size. The system assigns RAM to each address space as needed in a way that is totally transparent to applications. Applications have only a limited influence on this process.

All of an applications code and data, plus all DLL's accessed, must fit within it's 2GB address space. For some large applications (image and video editing, databases, and games) this can be a tight squeeze. And there are further complications. In many cases DLL's must be loaded to specific addresses, resulting in the address space being broken up into a number of smaller pieces. An application request for a large block of contiguous memory may fail, even when the total space is adequate.

Adding more RAM, even beyond 4GB when possible, does not help. The problem is a limited virtual space, not RAM. Most systems allow changing the address space division to allow 3GB for applications and 1GB for the system but this offers only limited relief. This is available only to applications that have explicitly indicated that they are compatible. Most aren't. There is a special technique available to applications but it has severe limitations and is not a real solution.

The real solution is to be found in a 64 bit OS. 64 bit Vista provides an 8 terabyte private address space for each 64 bit application. That is 4096 times the limit in 32 bit systems! The system address space is expanded to similar levels, leading to more efficient caching and avoiding a number of issues that sometimes occur. And the system need not have a great deal of RAM for applications to enjoy these benefits either. A 64 bit processor could theoretically offer an even greater space than that but there are practical issues to take into account.

But this advantage is primarily for 64 bit applications. 32 bit applications that are large address aware will receive a 4GB private address space. All others (the majority) will see no advantages, aside from the limited performance benefits

Conclusion:
The larger virtual address space is the prime advantage of a 64 bit OS, although at present few applications can benefit from it. Just about everything alse can be had in a 32 bit OS.

Thank you very much for the 32 bit and 64 bit. I had no idea about about either. Thanks a million. Now I have a question because I decided 32 bit for my Vista. My question is if I doublespaced my 32 bit and
is it better to doublespace 64 bit or 32 bit? I got about 2.5G more free space out of the deal. Do you think if I doublespaced 64 bit it would give me more? And I did not double the entire computer I did only 1/2 of my computer to see and so far nothing bad. I just wanted to tell about my self. I am happy to be apart of the vista forums. I am retired vet. of 24 years.
Thank you very much.

[LMiller7]

Quote

Thank you very much for the 32 bit and 64 bit. I had no idea about about either. Thanks a million. Now I have a question because I decided 32 bit for my Vista. My question is if I doublespaced my 32 bit and
is it better to doublespace 64 bit or 32 bit? I got about 2.5G more free space out of the deal. Do you think if I doublespaced 64 bit it would give me more? And I did not double the entire computer I did only 1/2 of my computer to see and so far nothing bad. I just wanted to tell about my self. I am happy to be apart of the vista forums. I am retired vet. of 24 years.
Thank you very much.

I am unfamiliar with "doublespace",except as a compressaion method once used with DOS and old versions of Windows. I suspect that you may be referring to NTFS compression which is quite different. In any event this has nothing to do with whether the OS is 32 or 64 bit. If you were to go with a 64 bit Vists you would have less free space as this OS is larger. As I mentioned, the primary advantage of a 64 bit OS is the much larger virtual address space. This has NOTHING to do with disk space.

I hope this helps.