|
With all of the
hype regarding the AMD64 instruction set architecture, you'd
think its success hinges solely on the proliferation of
64-bit operating systems and software. While it is
very important for the future of the AMD64 platform, 64-bit
operating systems and software are not an absolute necessity
in our opinion, at least for now. As you'll see a bit
later, the Athlon 64 FX-51's performance with today's
applications is stellar. The future promise of 64-bit
software is simply icing on the cake. We did however,
get a chance to work with a beta release of Windows XP
64-Bit Edition, and we can safely say Microsoft is on the
right track. Obviously, with a beta version there is
still work that needs to be done, between now and its
completion. However, even in this relatively early
stage it is a very stable and feature rich OS.
Windows XP
64-Bit Edition installed and ran just like the 32-bit
version of XP most of you are probably using right now.
We're also told a 64-bit version of Server 2003 is in the
works too, so Network Admins craving the benefits of 64-bit
computing should be happy early next year when these
operating systems are scheduled to be released.
SYSTEM PROPERTIES |
LOADING |
LOGIN |
On the surface
Windows XP 64-bit Edition looked much like XP Professional
with the "Luna" visual style de-activated. We dug into
things a bit further and noticed a few other differences as
well. Astute readers may notice that the System
Restore tab was missing from the System Properties page.
We don't have any official word from Microsoft yet, but we
suspect System Restore will be in the final release.
There were also two separate "Program Files" directories for
32-bit and 64-bit applications. Windows XP 64-bit
Edition has the ability to seamlessly run 32-bit software
through an emulation-like feature dubbed "WoW64", or
Windows on Windows 64. The name implies a 32-bit
version of Windows running on top of the 64-bit version,
like the way say OS9.2 runs over OSX in "Classic Mode" on
the Macintosh. However, this most certainly is NOT the
case. Wow64 is simply a layer between the application
and OS that translates 32-bit calls into 64-bit calls.
WoW64 is not full-scale emulation in the traditional sense;
after all the Athlon 64 can also natively run 32-bit code.
There are some minimal performance penalties associated with
running 32-bit applications on WinXP 64-bit Edition, but
they are nothing like the hits incurred with traditional
full-scale emulation. With WoW64, users can run 32-bit
applications side-by-side with 64-bit applications, without
ever knowing the translations are being performed in the
background.
Why
64-bit?
The advantages
of running native a 64-bit operating system and applications
are two-fold. First, the 4GB memory limit, associated
with 32-bit software and hardware architectures, is now a
thing of the past. Current versions of Windows XP can
address up to 4GB of memory, 2GB are allotted to the OS
while 2GB is available for running applications.
Microsoft's server OSes have the ability to address up to
32GB of memory through a technique known as PAE (Physical
Address Extension), but each application is still limited to
2GB. With Windows XP 64-bit Edition, the new memory
limit is 16 terabytes, or 16,000GB, and all of that RAM will be
available to the OS and applications. We doubt Windows
XP 64-bit Edition users will complain about memory
limitations anytime soon! The physical limits of
motherboards and memory will continue to hold users back
somewhat. For example, the Asus SK8N we used with that
Athlon FX-51 has only four DIMM slots. Even if you
could find 2GB memory modules, which happens to be the
largest we have seen to date, 8GB would be the maximum
amount of RAM you could install.
The more
tangible benefit to running a 64-bit operating system and
applications, is the code efficiency associated with it.
64-bit processors, executing 64-bit code, compiled with a
64-bit compiler, should perform marginally faster than
similar 32-bit; probably in the neighborhood of 5 - 15% or
more, depending on the type of application. There is
one major caveat to switching to a 64-bit OS, and that is
driver support. Manufacturers will have to re-compile
their drivers for the new OS. It will be some
time before 64-bit drivers reach the maturity level we all
enjoy today. Manufacturers won't have to completely
re-write their drivers from scratch, so with some luck, the
transition will go well.
 |
|
CPU-Z: A Closer Look |
|
There's More Than Meets The Eye |
|
Before we got to
the business of benchmarking the Athlon 64 FX-51, we spent
some time exploring its inner workings with the latest
version of CPU-Z. The information in the screenshots
below, show the CPU, cache configuration, motherboard
information and memory timings, but not everything was what
it seemed.
CPU-Z
CPU INFO |
CPU-Z
CACHE |
CPU-Z
MAINBOARD |
CPU-Z
MEMORY |
CPU-Z reports an
"FSB" speed of 200MHz. This is incorrect.
As we mentioned earlier, the idea of a "Front Side Bus" no
longer applies with the Athlon 64s. The memory
controller has been integrated into the processor's die, so
it runs at the same speed as the processor itself. The
CPU and chipset interface via the chip's HyperTransport
link, that operates at a separate frequency up to 800MHz.
The 200MHz CPU-Z is reporting, is from a clock generator
used to derive the processor's frequency, and that's it.
The cache information page accurately reports the FX-51's
1024K of full-speed L2 cache and the motherboard information
is also correct (However, we did upgrade the BIOS a few days
after taking these screenshots). On the memory page,
there is another data point that needs some clarification as
well. The memory page lists the number of memory
channels as "Dual". The FX-51 has a 128-bit memory
controller, which is twice as wide as the "standard" Athlon
64's 64-bit controller, but it technically is not a
dual-channel configuration. At 128-bits wide, the
Athlon 64 FX-51 offers the same theoretical peak of 6.4GB/s
of bandwidth at 400MHz as an i875 chipset controller.
The 64-bit controller found in the Athlon 64 3200+ peaks at
3.2GB/s when clocked at 400MHz.
Our
Test Systems & Initial Performance Info |