Linked by Thom Holwerda on Wed 2nd Dec 2009 23:25 UTC, submitted by estherschindler
Windows Among the factors to consider, as companies ponder Windows 7 migrations, is whether to run a 32 bit or 64 bit version of the operating system. IT Expert Voice looks at the reasons why and what companies are saying about their intentions to adopt each version.
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RE[4]: 32bits
by CodeMonkey on Thu 3rd Dec 2009 16:26 UTC in reply to "RE[3]: 32bits"
CodeMonkey
Member since:
2005-09-22

When you compile most Linux apps (or other platform) for 64-bit, most of the time they don't take advantage of 64-bit processing, except for the increase in memory available. So the vast majority aren't faster, they just have access to more RAM.


Not so. Regardless of Linux or Windows, when you compile an application for 64-bit, the compiler optimizes the code to utilize the extra general purpose and SSE registers. As silly as it sounds, often just compiling code to run on a 64 bit processor will show a not insignificant performance increase regardless of it's memory footprint.

What is a problem though is that many low level performance optimizations will likely have to be re-worked or re-thought in order to leverage the architecture effectively. Compilers are pretty good these days though often just a simple source-level re-compile for x64 can show a pleasant boost.

Reply Parent Score: 2

RE[5]: 32bits
by sbergman27 on Thu 3rd Dec 2009 16:34 in reply to "RE[4]: 32bits"
sbergman27 Member since:
2005-07-24

Not so. Regardless of Linux or Windows, when you compile an application for 64-bit, the compiler optimizes the code to utilize the extra general purpose and SSE registers.

Which, in the general case, makes surprisingly little difference. Or so it seems to me. Of course, the larger binaries hurt the effectiveness of the processor caches, thus offsetting the advantage to some degree or other.

Traditionally, we've been told that x86 was a register starved architecture. And yet it appears that it was not all that starved.

Reply Parent Score: 2