Anyone have experience with Acer netbooks ?

Tue Oct 20 19:33:37 UTC 2009

On Tue, Oct 20, 2009 at 03:04:43PM -0400, jing wrote:
> On Tue, Oct 20, 2009 at 10:53 AM, Lennart Sorensen
> <lsorense-1wCw9BSqJbv44Nm34jS7GywD8/FfD2ys at public.gmane.org> wrote:
> > I really really wish intel would stop being such assholes and stop making
> > chips without 64bit support.  These days wtih 2 to 4GB ram becoming
> > normal even in laptops, 32bit only cpus are totally stupid.
> 
> Completely innocent question out of curiosity; why all the craze for
> 64-bit processors?  I personally don't understand this request for
> 64-bit machines for average users.  Yes, I understand there may be
> some out there writing monster scientific or DB applications and
> what-not that require big memory spaces on monster servers.  But I
> just don't see how Firefox, OpenOffice, or MSOffice need 64-bits.  I
> don't even understand why people are asking for 64-bit machines on
> laptops.

Well a few simple reasons:

x86-64 is a better instruction set, and runs faster except in a few odd
cases.  This is very different from pretty much every other architecture
that has ever gone from 32 to 64bit.  Most slow down.

x86-64 mandates the use of SSE for floating point, while x86 uses x87.
This makes floating point much much faster, and avoids the awfullness
that is the x87 stack based FPU.  This means all 64bit software can
safely use SSE because it is a part of the instruction set.  x86 code
can not assume that if it wants to just work.  64bit mode also gets 64bit
registers, twice as many registers, and a number of other nice cleanups
to make code run faster in general.  To some extent the extra memory
space of x86-64 is just a bonus, the real feature is the much nicer
instruction set AMD designed.  Intel has always just piled on new
features.  AMD actually threw away legacy garbage from x86 when in
64bit mode.  Best thing to ever happen to the x86.

You get simple direct access to more than 3GB of ram, and each application
can use more than 2GB, including memory mapping files, which allows for
simpler and more efficient code when dealing with large files.

Most desktop machines these days come with 2+GB of ram, often 4 or 6GB,
which means a 32bit OS simply doesn't work anymore.  So the move has to
happen, and once the common desktop moves, a lot of software is going
to go 64bit.  Why would you want your brand new machine to be obsolete
out of the box?  You may not have more than 2GB ram now, but 6 month
from now they might have 4GB, and you still would like to be able to
run software on your machine a couple of years from now.

> As I understand it, current Intel 32-bit machines are not limited to
> only 4GB of RAM by enabling PAE.  Thus, the OS is more than capable of
> supporting and servicing more than 4GB of ram.  What a 32-bit machine
> cannot do, is it cannot allow a single process to address more than
> 32-bits of address space.  Thus, the extra ram will have to be
> distributed to feeding more than one application.  For example,
> Firefox gets 4GB of memory, and OpenOffice gets 4GB of memory, and
> there's no swapping on an 8GB machine (oversimplified, but not too far
> off, I hope).  Much of what makes a system run smoothly is caching and
> buffering, which is managed by the OS anyways so it's not like the app
> itself needs to address more than 32-bits of address space.

PAE is a disgusting hack, has very high overhead, and is no solution.
Still doesn't allow more than 2GB of memory space for each application.
You are better off loosing 800MB on a 32bit OS out of 4GB than to turn
on PAE.  Much better.

> I think I would be worried about the underlying design of Firefox if
> it started asking for more than 32-bits of address space as a
> fundamental requirement.  Again, I know there are people out there
> running big DBs and scientific genome computations and what-not.  You
> know who you are and you know you have big iron requirements, and
> there are machines you can buy for that.  I'm curious about average
> users that want 64-bits.

Oh firefox has issues, and it practically already tries to use that
much ram.

> So this goes back to my original question.  I hear from many people
> (especially consumer users) who push for 64-bit machines.  Why?  You
> can still pop more ram into it (AFAIK) and the OS still uses all the
> extra ram just fine.  The PAE-enabled 32-bit Linux kernel can service
> up to 64GB of RAM (again, AFAIK).  It seems like extra bits mean extra
> transistors and extra power burn, especially for laptops.
> Furthermore, special-case uses are covered by special registers
> already -- for example 64 and 128-bit FPUs and even some 256-bit SIMD
> units.  So why the push for 64-bits on everything?

It does NOT use it just fine.  It uses it at a serious performance hit,
and only by running many applications at once can you actually use
the memory.  PAE is only useful for database servers where more ram at
a lower speed was still better than less ram.  It is not a good solution
if you actually want performance.

The sooner all machines are 64bit capable the better.  Why intel decided
to make 32bit only atoms is beyond my imagination given all their other
CPUs already have 64bit support.  Of course AMD is starting to make lower
power Athlon II chips now, so perhaps this will make intel rethink things
for the better.

-- 
Len Sorensen
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