[lug] recommendation for a 64bit laptop

[steve at badcheese.com]

I've also gone the 64-bit route with my servers and have reverted back to 
32-bit due to a couple of issues:

6GB of ram turns into just greater than 3GB of ram (pointers and many data 
types are double the size when running in 64-bit mode).  C, perl, java all 
use pointers pretty heavily and a 32-bit app re-compiled on a 64-bit 
machine almost always bloats to near twice the resident size in memory.

Also, drivers are usually run in 64-bit compatibility mode when running in 
a 64-bit kernel.  This is not a native 64-bit driver and instead of being 
faster is actually slower than in 32-bit mode.  Drivers that I know of 
being this way: Adaptec & LSI RAID controller cards.

In short, stick with 32-bit unless you need memory access > 6GB in a 
single process.  Many performance improvements can be achieved with 
dual-core and it'll be much more noticable than running in 64-bit mode.

I've never actually installed any 64-bit kernel on a laptop though, just 
servers.  :)

- Steve

On Wed, 18 Apr 2007, Sean Reifschneider wrote:

> Date: Wed, 18 Apr 2007 04:58:55 -0600
> From: Sean Reifschneider <jafo at tummy.com>
> Reply-To: "Boulder (Colorado) Linux Users Group -- General Mailing List"
>     <lug at lug.boulder.co.us>
> To: "Boulder (Colorado) Linux Users Group -- General Mailing List"
>     <lug at lug.boulder.co.us>
> Subject: Re: [lug] recommendation for a 64bit laptop
> 
> On Tue, Apr 17, 2007 at 09:47:37AM -0600, Gary Hodges wrote:
>> machine with 2GB RAM.  I initially installed Kubuntu 64 and 64 bit IDL.
>> I forget the exact times, but one of my programs ran in about 10
>
> Probably an issue either with how you built the code or with the code
> itself.  I mean, I have tested things like code that uses native 64-bit
> ints on a 32-bit platform.  That had a significant performance impact,
> compared to using the 32-bit ints.
>
> That's one of the few times I've seen significant performance differences
> between a 32 and 64 bit distro on the same hardware.
>
> Sean
>

-- 
EMAIL: (h) steve at badcheese.com  WEB: http://badcheese.com/~steve