Re: I think I'm ready to give up on x86_64

["Shirley Márquez Dúlcey" <user=15@nabble.blu.org>]

 David Kramer wrote: 

> Before I waste more time tracking down problems caused by running 
> x86_64, I need to decide if it's actually worth it.  From what I 
> understand, the only advantages of 64 bit over 32 bit are access to more 
> than 4GB RAM (not a problem for me, since I only have 2GB), and memory 
> mapping large files (not an issue for the same reason).  Am I missing 
> something? 

On AMD-based systems, x86_64 also has a 10-20% performance edge over the 
32-bit x86 build when running 64-bit applications on Linux. It mostly 
seems to come from the fact that the x86_64 architecture has twice as 
many general purpose registers, so the code needs fewer instructions. 
Code SIZE, on the other hand, stays about the same, because 64-bit 
instructions tend to be longer because of the bigger pointers. 

On the Pentium 4 and Pentium D processors with 64-bit support, x86_64 
runs no faster than x86, suggesting that the bottleneck in those 
processors was instruction fetch rather than execution. I haven't yet 
seen any comparative benchmarks for the Core 2 series. 

10-20% isn't a very big deal for most people. A desktop user would 
barely notice it, and it goes away if you spend your time running 32-bit 
applications. And if you run 3D applications, forget x86_64, because I 
don't think any of the proprietary video drivers come in 64-bit builds 
yet. All in all, it may not yet be worth the trouble for desktop Linux 
users, though I think x86_64 does have a place in the server room. 


-- 
This message has been scanned for viruses and 
dangerous content by MailScanner, and is 
believed to be clean. 

_______________________________________________ 
Discuss mailing list 
[hidden email] 
http://lists.blu.org/mailman/listinfo/discuss