Some comments and observations after reading through this thread:
1. most desktop applications (including those that are built to use 64 bit
hardware) will not benefit very much if at all from the larger virtual or
real address space available in 64 bit Windows. Most such applications
typically use considerably less than 1 GB of address space anyway (use Task
Manager, or Performance Monitor to verify this for yourself) so the larger
virtual address space available is not relevant to them.
2. most desktop users don't have more than 4 GB of RAM, so having the
"ability" (in the OS) to support more won't be relevant to them. This will
change over time, but there a quite a few "current product" (desktop)
motherboards that support a maximum of 4 GB RAM or less anyway. I agree
that the "average" or "typical" RAM complement in desktops and laptops is
bound to increase as times go by, but it will be a while before most
"typical" users will benefit from more than 4 GB RAM.
3. The larger registers (word size) used in 64 bit processors will be of
most benefit, speed wise, to applications that perform a large number of
high precision arithmetic operations or otherwise are designed to use the
larger registers, such as scientific data modeling, high performance games
and image processing. The "Panorama Factory" mentioned in some of the posts
is one such application. Typical desktop applications (e.g. word
processors) will most likely not benefit appreciably from being re-built
(re-compiled) to use 64 bit instructions because of the byte (character)
oriented nature of their processes. Some current Intel and presumably AMD
or other processors do have specific instructions for performing multiple
byte oriented operations concurrently which may also provide a speed boost
for applications built (compiled) for 64 bit operation - for more
information about this stuff, see for example
ftp://download.intel.com/technology/architecture/new-instructions-paper.pdf)
- keep in mind that applications have to be specifically coded (or built
with a development tool that knows how to use them) to use these "enhanced"
instructions to actually benefit from these architectural "advances".
4. 64 bit operating systems will, generally speaking, require more RAM to
support the same workload than 32 bit operating systems. This is because
the data structures used by the OS to manage virtual memory, processes etc.
have larger "rows" (e.g. 8 bytes instead of 4 bytes per "item"). The impact
of this will increase as the number of processes increases (for example in a
Terminal Server supporting a large number of users). Switching from 32 bit
to 64 bit OS for such systems may be actually reduce performance unless
there is sufficient RAM in the hardware. If the hardware is RAM rich (e.g.
16 GB or more), then the additional real memory capacity will help such
systems to support higher loads if they are memory constrained on 32 bit
systems.
5. Applications (systems) that can benefit from lots of virtual address
space and lots of RAM (e.g. database management, mail servers, search
engines etc.) can really take advantage of 64 bit systems because of the
much larger virtual address spaces available per process and the increased
maximum RAM supported by the hardware and the operating system. Systems
used to support multiple Virtual Machines will benefit from more RAM. Keep
in mind that 32 bit Windows servers can use more than 4 GB of RAM quite
effectively using Processor Address Extensions (the PAE option), so 64 bit
Windows is not a pre-requisite for this, although it may be advantageous.
Be aware that there are no currently available processors or operating
systems in the "Windows/Intel" line that actually implement a full 64 bit
real or virtual address space. See
http://members.shaw.ca/bsanders/WindowsGeneralWeb/RAMVirtualMemoryPageFileEtc.htm#64Bit
for more information about this.
6. 64 bit Windows is still relatively new, particularly so in the desktop
(client) market. This means that there is lots of hardware for which there
are no 64 bit drivers yet. Some "older" (the meaning of "older" is
subjective - different vendors interpret it differently!) will never have
drivers for 64 bit Windows. So, just as when Windows 2000 and later Windows
XP was released, early adopters often find their existing (and newly
purchased) hardware is "not supported".
7. the bottleneck in many cases is disk access, not processor or memory
speed or capacity. Additional RAM can help to provide optimization of
directory and file caching, but the only solution to the disk bottleneck is
more physical disks (e.g. using "spanning") or disks, controllers and
chipsets with higher data transfer rates.
Two conclusions:
A. 64 bit system overall is not necessarily "faster" or more responsive than
a 32 bit system on the same or equivalent hardware. In some cases (when RAM
is in short supply), 64 bit system may be slower or have less capacity.
B. if you are prepared to deal with frustration, search for drivers,
interact (often with little success) with vendor support organizations, and
want to be on the leading (bleeding?) edge, then by all means use 64 bit
Windows. On the other hand if you just want your system, peripherals (e.g.
scanners, printers or whatever) to work "out of the box" without hassles,
for the time being at least, stick to 32 bit Windows.
C. Generally and for "typical" uses, don't expect any big difference in
performance with 64 bit over 32 bit Windows.
--
Bruce Sanderson MVP Printing
http://members.shaw.ca/bsanders
It is perfectly useless to know the right answer to the wrong question.
Phillip Pi said:
Hi.
Since I installed both 32-bit and 64-bit Vista Ultimate Edition on my old
test machine (ASUS K8V SE Deluxe, Athlon 64 3200+ [754 CPU], 512 MB of
RAM, SATA HDD, etc.), I notice the speeds are identical. I can't see and
feel any improvements. I did install the ATI Radeon 9600 AIW drivers to
help the video speed, but I just don't see the speed differences. Am I
expecting too much or missing something? I don't have any other program
installed so far. It's just a bare Vista with the latest ATI/AMD video
drivers from ati.com/amd.com.
Thank you in advance.
--
Phillip Pi
Senior Software Quality Assurance Analyst
ISP/Symantec Online Services, Consumer Business Unit
Symantec Corporation
www.symantec.com
