Hi,

2013/5/24 Jabari Z. <lists / ruby-forum.com>:
> Heesob Park wrote in post #1109662:
>> Hi,
>>
>> 2013/5/21 Rob Biedenharn <rob / agileconsultingllc.com>:
>>>> For a 64-bit build numbers should be Fixnum all the way up to (2**63-1).
>>> Fixnum#size returns the number of bytes in the representation. On a 32-bit
>> system, you'd get 1.size==4 instead.
>>>
>>> -ROb
>>
>> Windows uses LLP64 data models, which maintains compatibility with
>> 32-bit code by leaving both int and long as 32-bit.
>>
>> C:\Users\phasis>ruby -ve 'puts 1.size'
>> ruby 2.0.0p195 (2013-05-14) [i386-mingw32]
>> 4
>>
>> C:\Users\phasis>ruby -ve 'puts 1.size'
>> ruby 2.0.0p195 (2013-05-14) [x64-mingw32]
>> 4
>>
>> C:\Users\phasis>ruby -ve "puts ['a'].pack('P').length"
>> ruby 2.0.0p195 (2013-05-14) [i386-mingw32]
>> 4
>>
>> C:\Users\phasis>ruby -ve "puts ['a'].pack('P').length"
>> ruby 2.0.0p195 (2013-05-14) [x64-mingw32]
>> 8
>>
>> Refer to http://en.wikipedia.org/wiki/LLP64#64-bit_data_models
>>
>> Regards,
>> Park Heesob
>
> So what is the effective difference between what you can/can't do with
> the 64-bit version versus 32-bits? Greater memory space, etc?
>
The terms 32-bit and 64-bit refer to the way a computer's processor
(also called a CPU), handles information. The 64-bit version of
Windows handles large amounts of random access memory (RAM) more
effectively than a 32-bit system[1]

> I want to do math with large numbers and assumed the 64-bit version
> would be faster for large numbers, but is that assumption true?
>
Win 64 is usually SLOWER than Win 32, because every instruction and
every piece of data has to be loaded in a larger chunk, and access to
RAM is a bottleneck. Win 64 will be faster only when large amounts of
consecutive data need to be read, such as in heavy graphics
applications, video editing etc.[2]

Refer to
1. http://windows.microsoft.com/en-id/windows7/32-bit-and-64-bit-windows-frequently-asked-questions
2. http://www.makeuseof.com/tag/difference-32-bit-64-bit-windows/

Regards,
Park Heesob