That memory upgrade you wanted to get your Vista PC past 4 GB
of RAM is going to cost a lot more. You'll have the price of the RAM
and have to pay an extra $189.99 for
a copy of 64-bit Vista.
That is if you are lucky enough to be able to use it. You see, most
installed copies of Vista are the 32-bit version. 32-bit means that
the
most RAM you can theoretically use is 4 GB. You will actually
have less, because peripherals and other devices use the same address
space. Each device reduces your
access to memory, bringing things closer to 3 GB.
The only way to access more than 4 GB of RAM is to buy the 64-bit
version of Vista.
No Upgrade for You
Why can't you just buy the cheaper upgrade version? The scoop is
that the installer is 64-bit, so unless you already have a 64-bit
version of Windows XP installed, you can't run the upgrade and thus
have to buy a full version to move away from 32-bit.
As a bonus, you get a few extra problems with Vista. The 64-bit
version needs a 64-bit computer. Intel's Core Duo and earlier CPUs were
not 64-bit, but the newer Core 2 Duo and the Xeons are. So you
may have to buy a whole new computer if you need more than 4 GB of
RAM!
The reason most consumer PCs still have the 32-bit version of Vista
is that old programs and drivers may not be compatible with 64-bit
Vista. Therefore you risk upgrading only to have your applications or
peripherals stop working.
UPDATE: Several readers report that you can upgrade from 32-bit Vista
to 64-bit Vista almost for free. Microsoft only charges for shipping
and handling. Also, the 64-bit installer will work over a 32-bit install,
but you have to boot from the install disc. Thanks to the sharp readers
who provided these datails!
It Doesn't Have to Be This Way
This whole situation makes no sense. Apple added 64-bit support to
Mac OS X 10.4 "Tiger" on G5 Macs (CPUs prior to the G5 don't
support 64-bit operation) back in 2005. Apple combined support for both
32-bit and 64-bit into one operating system.
As a Mac user, I never had to worry about which version to buy or
use. We've had the best of both worlds for years. I've got 5 GB of
RAM in my Mac Pro, and I love
how it improved performance and stopped the constant need to write to
the hard drive.
I can understand that Windows XP had to have two different versions.
It came out before people started making 64-bit computers for
consumers. But AMD began making 64-bit processors
back in 2003, so Microsoft has had years since then to put together
a plan to unify the operating system for both 32-bit and 64-bit.
What I don't understand is why Microsoft couldn't get this all
sorted out in time for Vista - even Windows 7 is said to be
coming in separate 32-bit and 64-bit versions.
Too Many Options
Why do I care? Well, Vista is just another application that can be
run on my Mac. Choosing a version of Vista is confusing enough with the
choice of Home, Premium, Business, and Ultimate - and now I have to add
whether to buy 32-bit or 64-bit!
When I searched for help on which version to buy, I found articles
like Performance
Shootout: Vista 32-bit versus Vista 64-bit comparing 32-bit to
64-bit Vista. They failed to mention the 4 GB memory limit. I
searched through a dozen different sites to figure out which version to
buy without learning about the memory limit.
How can a site with the name "ExtremeTech" fail to mention that a
computer with more that 4 GB memory is an issue? I first heard
about it on the MacWindows
website.
I see a perverse acceptance of the 4 GB limit as a failure of
the PC industry. This limit, set by Microsoft and other software
vendors stuck at 32-bit, is holding back computers in general. No
laptop that I could find can handle more than 4 GB. Even Apple,
which now uses off-the-shelf components, has this same limit on its
laptops. Only the Mac Pro and workstation computers from other vendors
are capable of handling more than 4 GB.
In a world where we can buy an 8 GB
flash drive for as little as $25, it feels unreal that you can't
buy inexpensive computer RAM with more than 2 GB capacity. Of
course this makes sense if you're stuck using 32-bit Windows XP or
Vista and can't use the extra RAM anyway.
Thinking Different
Apple's engineers dealt with the issues involved in having 32-bit
and 64-bit code integrated into one operating system. I'm sure it would
have been easier for Apple to have two different versions of OS X.
I like the seamless transition - it allows for gradually moving away
from 32-bit computing, and the user doesn't even need to know that it's
happening.
As a Mac users, I didn't know that there was an issue. Now that I
do, I'm even happier with my purchase of a Mac Pro, because it's
already at the 64-bit level. It will therefore remain current for years
to come as we wait for the Windows world to catch up.
Apple is highlighting that Snow Leopard will have
access to huge amounts of RAM (16 TB) because of its 64-bit
underpinnings. Maybe someday they'll be selling computer RAM in
1 TB sticks. Just imagine what kind of application could take
advantage of that much memory!
If more people don't switch to 64-bit computing, we may never find
out. We can't expect Apple to bring the computing industry into the
21st century by itself - or can we? 
