Graphics performance and 64 bit OS

  • Thread starter Thread starter Ken
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K

Ken

I was wondering whether we can expect a performance increase with existing
graphics cards if we use a 64 bit operating system and a 64 bit driver over
a 32 bit setup.

Any ideas?

Thanks
 
Ken said:
I was wondering whether we can expect a performance increase with existing
graphics cards if we use a 64 bit operating system and a 64 bit driver over
a 32 bit setup.
Click to expand...

Yes, even with 32-bit games. Of course that requires ATI to get off their
arses and write a 64-bit driver.

K
 
All things being equal, a 64-bit machine (CPU + OS) will typically be
*slower* than a 32-bit machine. Now, all things are *never* equal and
the current line-up of 64-bit CPUs (AMD64, Opteron, etc) have many
hardware enhancements (extra registers, larger caches, faster memory
interconnects, etc) that will increase overall performance.

That being said, if you own a 64-bit CPU and are running in 32-bit mode,
will you get better performance simply by installing WindowsXP-64 and
some 64-bit drivers? Possibly, but only if the OS/drivers have been
tweaked to take advantage of the CPU/chipset's new features. The
general "64-bit-ness" of the software does not make anything faster over
32-bit.
 
I was wondering whether we can expect a performance increase with existing
graphics cards if we use a 64 bit operating system and a 64 bit driver over
a 32 bit setup.

Any ideas?

Thanks
Click to expand...

AMD and Crytek will be making a free-download 64-bit version
of Far Cry available to purchasers of the game.

Go to:-

www.amd.com/farcry

for all the details.

John Lewis
 
cK-Gunslinger said:
All things being equal, a 64-bit machine (CPU + OS) will typically be
*slower* than a 32-bit machine. Now, all things are *never* equal and
the current line-up of 64-bit CPUs (AMD64, Opteron, etc) have many
hardware enhancements (extra registers, larger caches, faster memory
interconnects, etc) that will increase overall performance.

That being said, if you own a 64-bit CPU and are running in 32-bit mode,
will you get better performance simply by installing WindowsXP-64 and
some 64-bit drivers? Possibly, but only if the OS/drivers have been
tweaked to take advantage of the CPU/chipset's new features. The
general "64-bit-ness" of the software does not make anything faster over
32-bit.
Click to expand...

I'd be interested in knowing on what you base this conclusion.

FWIW, with the Opterons Linux shows a marked performance improvement when
recompiled as 64-bit code.
 
That's *exactly* what I just said. *If* the code has been recompiled to
take advantage of the new 64-bit features, it will perform better;
otherwise, not.

A 64-bit CPU gives you the ability to use 64-bit memory address,
allowing you to have a *lot* more addressable memory that 32-bit (which
are 'limited' to ~4GB). Also, the registers are 64-bit, allowing you do
perform 64-bit calculations in a single step, as opposed to doing them
twice with 2 32-bit numbers. That's it. That's all that's required for
a CPU to be '64-bit'. If your applications use a lot of 64-bit
number/integers (most do not), then you might see some speedup,
Otherwise, not. Simple.

64-bit = 'more memory, larger native numbers'
64-bit != 'inherently faster performance'

But like I said before, all the new 64-bit CPUs include numerous other
architectural enhancements that will outperform current 32-bit CPUs, so
your apps *will probably* perform better on an Opteron than your current
p4, but *not* because the Opteron is 64-bit, but rather in spite of it.
 
I was wondering whether we can expect a performance increase with existing
graphics cards if we use a 64 bit operating system and a 64 bit driver over
a 32 bit setup.

Any ideas?
Click to expand...

Yes, you will see improvements. But M$ is currently screwing AMD in
the ass... they are promoting "Windows64" for Intel's Xeon and the
failing CPU... while AMD is selling AMD 64s out the butt.

Even with todays crappy 32bit Windows (hmmm... Linux64bit has been
AMD64 compatible for over a year - shows HOW lame M$ is). The AMD64 is
faster than the 32bit AMD CPUs at the same or less clock rates.
 
cK-Gunslinger said:
That's *exactly* what I just said. *If* the code has been recompiled to
take advantage of the new 64-bit features, it will perform better;
otherwise, not.

A 64-bit CPU gives you the ability to use 64-bit memory address,
allowing you to have a *lot* more addressable memory that 32-bit (which
are 'limited' to ~4GB). Also, the registers are 64-bit, allowing you do
perform 64-bit calculations in a single step, as opposed to doing them
twice with 2 32-bit numbers. That's it. That's all that's required for
a CPU to be '64-bit'. If your applications use a lot of 64-bit
number/integers (most do not), then you might see some speedup,
Otherwise, not. Simple.

64-bit = 'more memory, larger native numbers'
64-bit != 'inherently faster performance'

But like I said before, all the new 64-bit CPUs include numerous other
architectural enhancements that will outperform current 32-bit CPUs, so
your apps *will probably* perform better on an Opteron than your current
p4, but *not* because the Opteron is 64-bit, but rather in spite of it.
Click to expand...

That's a nice opinion, now, do you have any examples using real-world
processors and real-world code to support it?

What you claim to be saying and what you are actually saying seem to be more
than a little at variance. If the advantages you cite are the only ones
that a 64-bit processor provides then why does 64-bit Linux run so much
faster than 32-bit Linux on the same hardware?
 
*sigh* One more time, then I give up:

----
FROM: http://www.osnews.com/story.php?news_id=5768

"So while the tests I ran were on only a few applications and in limited
ways, the results seem to show that indeed 64-bits do generally run
slower. However, there are there are a few issues to consider."

----
FROM: http://arstechnica.com/cpu/03q1/x86-64/x86-64-1.html

"...the only kind of performance increase that you can expect from a
straight 64-bit port is whatever additional performance you get from
having more memory available. As I said earlier, 64-bitness, by itself,
doesn't really improve performance for anything but the rare 64-bit
integer application. In the case of x86-64, it's the added registers and
other changes that actually account for better performance on normal
apps like games."
----

I'm not exactly just pulling random opinions out of my ass here. I have
worked for several years in the software industry and have designed and
run code for 8-, 16-, 32-, and 64-bit processors. The only statement
I'm trying to make, which I've pointed out with each post to this
thread, is that "64-bit does not mean inherently faster performance."

You even seem to support my statement, with your argument of "... then
why does 64-bit Linux run so much faster than 32-bit Linux on the same
hardware?"

The answer is obvious and was addressed in my previous post with the
second statement: "*If* the code has been recompiled to take advantage
of the new 64-bit features, it will perform better; otherwise, not."
The 32-bit Linux code running on Athlon64 architecture cannot "see" the
extra registers, and cannot therefore use them in anyway. Only by
recompiling the code with the 64-bit flag can you 'force' the code to
recognize the extra hardware and utilize it.

I fail to see the "variance" in my claims and I am sorry that I cannot
be anymore clear or straightforward with "my nice opinions."
 
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