[D-community-offtopic] Maximum RAM

[André Nunes Batista]

On Fri, 2013-12-13 at 14:25 +0100, Ralf Mardorf wrote:
> On Fri, 2013-12-13 at 10:27 +0200, Andrei POPESCU wrote:
> > On Jo, 12 dec 13, 09:56:29, Ralf Mardorf wrote:
> > > 
> > > Rumours about disadvantages or are there real drawbacks for some use
> > > cases?
> > > 
> > > The Windows crew? I love Linux, but want to run Windows VSTs and
> > > something like this?
> > > 
> > > I've got doubts that there are valid reasons to prefer 32-bit over
> > > 64-bit in 2013/2014, assumed the hardware does allow 64-bit.
> > 
> > And who determines the validity of my reasons? :p
> 
> I'm asking, you don't mention your reasons. You might have noticed that
> I'm going to install 32-bit Debian stable, to see if there should be
> advantages.
> 

Ralf, I once said I'd use you as my personal debugger and I also had a
bit of a rant on 64 x 32 bit architecture industry pace + devs behaviour
so I feel the need to reply to you and others.

When I said that I was running on a system with low physical memory
available (2GB) but a 64 intel chip. On my previous knowledge on how
processors work I made a wise guess that 64 bit computation would
require physical memory of near the same size to store results and that
if compilers were not optimized for 64bit arch, 32bit code wouldn't make
much of a use of new assembly optimized instructions for 64 and just run
32bit instructions in parallel. But parallelism have always been said to
be the quintessential computing problem. So I assumed it would do a bad
job and store much more data on memory than what it would actually need
in a 32bit arch.

Since then I've bought more mem and now I run on 4GB DDR2 (ow consumer
market has past that years ago) and have installed amd64 kernel. I've
noticed memory consumption go up as I was expecting, but the system was
not barebones nor did I care too much if I was right or wrong on my
previous assumption so you should not take my word for it.

I think I'd need to run tests and read a pile of docs on compilers to
understand the degree to which my assumption might be mistaken, but
right now I do not have time or hardware available to play with so I
guess I shall remain with my prejudices for a while longer.

-- 
André N. Batista
GNUPG/PGP KEY: 6722CF80