64 bit verus 32 bit os

Thread Starter

vustudent

Joined Mar 11, 2009
38
Since a 64 bit operation system runs with more bits to a processor, would it be inefficient and possibly slower in performing certain trivial tasks than the 32 bit os?

For example, if you are performing addition of two numbers:
A = decimal 1
B = decimal 3

where under a 32 bit os A would be 31 zeros and a one, and B 30 zeros and two ones. While under a 64 bit os, there would be more zeros passed to the processor describing the same number and then performing the addition.
 

Potato Pudding

Joined Jun 11, 2010
688
More parallel bits will generally be faster and no slower.

Look at the bitwidth as 64 logic streams with a carry.

Each logic stream is as fast as it is and doesn't worry about how many logic streams are in parallel.
 

marshallf3

Joined Jul 26, 2010
2,358
Actually makes no difference with simple things, it's when you get into the more complicated programs that the CAPABILITY of being able to handle a 64 bit wide bus comes into play.

For ages the command set of the actual thinking part of a CPU was only 8 bits wide anyway and may still be for all I know.
 

kingdano

Joined Apr 14, 2010
377
its definitely on the programmers to utilize the 64-bit architecture and take advantage of the extra processing gusto.

if you run a 32-bit program on a 64-bit OS you gain little (if any) performance.

but true 64 pit programs do run much more quickly than the same program written in 32-bit.

LabVIEW for example - the 64 bit version runs more smoothly in me experience.
 

tom66

Joined May 9, 2009
2,595
The ability to move 64 bits at a time is an advantage. For example, the 32 bit version of glib's strcpy copies up to 4 bytes at a time, while the 64 bit version copies up to 8 bytes a time: 2x speed increase.
 

marshallf3

Joined Jul 26, 2010
2,358
I've found little that can take advantage of 64-bit although the gamers have, I've also found a lot of things that run on 32 but won't run on 64 without "cheating" so to speak.

Out of all the PCs on my home network only one runs XP Pro 64, it's a file server and you need a 64 bit OS in order to take advantage of GPT/GUID partitioning so you can break the 2 TB limit on hard drive RAID sets.
 

studiot

Joined Nov 9, 2007
4,998
The ability to move 64 bits at a time is an advantage. For example, the 32 bit version of glib's strcpy copies up to 4 bytes at a time, while the 64 bit version copies up to 8 bytes a time: 2x speed increase.
This is an oversimplification, stemming from a fundamental misconception.

The efficiency, or otherwise, of a processor, depends largely upon the match of the 'real' data width being processed with the address width.
Don't forget that much processor work is taken with calculating and processing addresses.

A processor with a 64 bit address space and 64 bit data space is no more or less efficient than one with a 4 bit address space and 4 bit data space.
 

nsaspook

Joined Aug 27, 2009
13,079
This is an oversimplification, stemming from a fundamental misconception.

The efficiency, or otherwise, of a processor, depends largely upon the match of the 'real' data width being processed with the address width.
Don't forget that much processor work is taken with calculating and processing addresses.

A processor with a 64 bit address space and 64 bit data space is no more or less efficient than one with a 4 bit address space and 4 bit data space.
In a threaded and/or multitasking OS even with less than 32 bits of memory the ability to use 64 bit atomic operations for locks or synchronization can make context switches/OS system calls faster by packing structures into a 64 bit register. The ability to crunch twice the data in the same clock cycles is pretty cool also when using written for 64 bit tools.

http://technet.microsoft.com/en-us/library/dd630755(office.12).aspx
 
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