[dba-Tech] A few hardware/memory questions

jwcolby jwcolby at colbyconsulting.com
Sat May 17 21:04:07 CDT 2008


 > 1.) I'm going to upgrade my pc -- was going to go all the way to 2 
gigs until the recent conversation about Windows XP not being able to 
use more than 1.2, so my question is, why pay for 2 if the system's only 
going to use 1.5?

Uhhh... I think there has been a failure to communicate... (one of my 
favorite movie lines).

Windows XP x32 can use up to 4 gigabytes of RAM.  Windows XP x64 can use 
... unknown but way more than you can fit in your machine.

The x32 4 gig limitation comes from the fact that using a 32 bit address 
register you can only physically access 2^32 addresses which equals 4 
gigs.  NOW, having said that, any memory that is on perepheral devices 
such as (for example) 128 or 256 megs on a video card have to be 
"mapped" into that same 4 gigs of ram space, so what happens is that 
Windows carves "holes" in that 4 gigs and "maps" the video memory into 
that hole, so that you end up with 4 gigs of memory MINUS the "mapped" 
memory from your video card.  USUALLY you will end up with something 
between 3.25 and 3.6 gigs of RAM if you install 4 gigs of memory in a 
windows x32 machine.

What happens if you install less than 4 gigs (only 2 gigs)?  Windows no 
longer has to carve the holes out to map the memory of the video card so 
you end with with ALL of that 2 gigs available as memory.

 > 2.) Is there a modem/wireless router combo? I'm using cable Internet. 
If I have to buy both, seems like someone would be making a single unit 
that does both by now.

I don't know but the cable company provides whatever they provide.  They 
usually do not give (or at least offer) you a choice.  Most of us just 
go buy a wireless modem of our own choice to place "behind" the cable modem.

John W. Colby
www.ColbyConsulting.com


Susan Harkins wrote:
> 1.) I'm going to upgrade my pc -- was going to go all the way to 2 gigs until the recent conversation about Windows XP not being able to use more than 1.2, so my question is, why pay for 2 if the system's only going to use 1.5? 
> 
> 2.) Is there a modem/wireless router combo? I'm using cable Internet. If I have to buy both, seems like someone would be making a single unit that does both by now. 
> 
> Susan H. 
> _______________________________________________
> dba-Tech mailing list
> dba-Tech at databaseadvisors.com
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