PDA

View Full Version : speed difference with new 64Bits


Halford
10-07-2004, 11:27 PM
Hi everyone,

just to have your opinion or experience, I'm a 3D max user and I'm wondering if there will be much difference if I switched to a 64bits system.

do you know if Max has problems on a 64bits, or does it gain speed? is the difference worth the money?


thank you a lot.

Hal.

-Vormav-
10-07-2004, 11:55 PM
Currently, there isn't really any major advantage to 64-bit processors...I don't think any of the big applications have been coded to take advantage of 64-bit systems yet, except maybe on Linux. But you shouldn't experience any problems with it - they support 32-bit software just fine. Currently, my AMD64 2800 is performing about the same (just a little bit slower) than my 3ghz P4.

lots
10-08-2004, 12:07 AM
Until your specific software (and OS) has been rewritten for 64bit computing, you wont see any benifits from a 64bit capable CPU. At least from its 64bit abilities. But there is more to the Athlon 64/FX/Opteron than just its 64bit extentions. They are also very capable 32bit CPUs and will work just fine with 32bit software and OSs. The onboard memory controller is a major plus, and these chips can stack up well to Intel's current offerings. Also in alot of server and number crunching areas (rendering is among these), these chips accell in as well.

So, if you are asking is there any benifit from the 64bit? At this time no. Neither Windows XP or 3dsmax are 64bit currently, meaning no boost from the 64bit capable P4s, Xeons, Athlon64/FX, or Opterons. Though because these 64bit chips are capable of 64bit arithmatic, rendering has the potential to speed up and look better, if the software is written for it. This means you will ned a 64bit OS first and formost, and the other apps to go with it.

There is a benifit in 32bit applications today tho. These chips are 32bit capable as well. And since they are great improvements (at least in AMD's case) from thier previous line, they will be better at 32bit apps. This includes current versions of windows and for you, 3dsmax.

I doubt you will see much speed improvments from 64bit for a while. Windows XP 64 is slated for release early next year, but I dont know if 3dsmax or any of the other big CG apps are ready to move to 64bit when XP64 is released.. And until that happens you wont see improvements in speed, due to 64bit anyway.

heavyness
10-08-2004, 03:54 AM
i've heard they run 32-but apps pretty solid, but i can't back it up with any numbers. but like lots said, its a investment for the future and they cost the same [if not less] then the 32-bit brothers and sisters.

Vertizor
10-08-2004, 04:37 AM
i've heard they run 32-but apps pretty solid, but i can't back it up with any numbers. but like lots said, its a investment for the future and they cost the same [if not less] then the 32-bit brothers and sisters.
Well by the time the 64-bit OSes come out there will be better chips out too and the 32/64 bit chips mentioned here will be considered "old." And the price difference between a regular Athlon XP/MP vs. the 64-bit flavors is quite significant actually (the 64 bit ones being more expensive).

At least in the case of AMD chips, the biggest advantage of the AMD64 family compared to AMD's 32 bit line is that the AMD64 chips scale to higher clockspeeds.

lots
10-08-2004, 05:22 AM
Even if the 64bit on the newest chips is useless at the moment, it also doesnt mean they're a waste. For the AMD side of the fence, the Athlon64 and Opterons boast some pretty significant gains from the previous Athlon XP line in 32bit apps. Sure they're a bit pricy, but in multi CPU setups (Opteron) they scale very well. And they're about the same cost as Intel's current offerings. The Intel side of the fence is not as impressive, if you compare the gains to the previous generation of P4s. But this is because it is essentially the same chip with more GHz and 64bit enabled..

Thalaxis
10-08-2004, 05:44 PM
Actually, the Athlon64 adds (over the Athlon) a much faster memory subsystem, bigger and/or faster caches (depending on how much you're willing to spend), improvements throughout the processor's "front end" (instruction decoding and scheduling, branch prediction, etc) that lead to better performance per clock cycle, on average.

And when in 64-bit mode, it adds a flat register model with more registers, which is probably going to be a bigger value-add than the extra memory support for a while, because that leads to potential performance improvements, while 64-bit memory addresses increase program size and therefore memory overhead, and it's not going to be the case that everyone with a 64-bit setup will need (or have) more tham 4 GB of memory right away.

Not that I think it will be very long until the memory limit becomes relevant, though.

Vertizor
10-08-2004, 06:01 PM
All it takes is one of the major renderers build a command-line version that uses 64-bit code. There's 2 approaches:

1. Stand-alone command line renderer. Slap it in a Linux/Opteron render slave in 64-bit mode.

2. AMD64 can execute both 32 and 64 bit code in the same environment right? Meaning without rebooting into a true 64 bit OS. There are 64 bit math libraries developers can use to build their renderers. Apple already started doing this with their G5 systems and Panther OSX. OSX 10.3 comes with 64-bit libraries that are used when running on a G5 system, with a 32-bit version of the same libraries as a fall back.


64-bit computing is nothing new, the feature that really is important - and I regret not having more info on it - is that AMD64 can execute 32 and 64 bit code. So we don't necessarily have to wait for 64 bit Windows. We just need software compiled specficially for these processors. The whole emphasis on 64 bit Windows is: for typical "everyday" software like your word processor, office apps, etc. they rely on the OS and core GUI libraries (they make more system calls than running their own code). So to see more significant gains in performance, the OS and sub system needs this overhaul. Individual applications that are more CPU intensive running their own internal code can take advantage of x86-64 right now.

Goon
10-08-2004, 06:09 PM
would 64bit support lead to better floating point performance during rendering? Or are double (64bit) floating point numbers avoided?

Thalaxis
10-08-2004, 07:08 PM
64-bit computing is nothing new, the feature that really is important - and I regret not having more info on it - is that AMD64 can execute 32 and 64 bit code.

Most code running even on modern 64-bit RISCs is 32-bit code, so that's nothing unique. The advantage that AMD64 has is that it can run 32-bit x86 code. Since that's close to 90% of the commerical and open-source codebase right there, that's more than just huge.


So we don't necessarily have to wait for 64 bit Windows. We just need software compiled specficially for these processors.
<snip for brevity>
Individual applications that are more CPU intensive running their own internal code can take advantage of x86-64 right now.
Not quite. The catch is that x86-64 is a superset of x86-32. x86-64 has a mode that makes it look like a 32-bit machine, and 32-bit software is simply unaware of the extra stuff. However, if the OS is running in 32-bit mode, then the processor CANNOT switch to 64-bit mode.

In 64-bit mode, there are two "sub modes". One is 32-bit compatible, and IIRC it's called compatibility mode. The other is I believe called long mode, and it's 64-bit only.

And in 64-bit mode, there are some things that simply will not work due to compatibility issues: 16-bit real-mode (I think) in accessible when the processor is set to 64-bit.

The compatibility mode is transparent to 32-bit software, so only the system services need to know that there is a difference. It has to be able to convert between the 32-bit software's memory map to the global 64-bit virtual memory map.

So, to sum up (and hopefully allay confusion):
With a 32-bit OS, you have a 32-bit machine.
With a 64-bit OS, you have a 64-bit machine that can masquerade as a 32-bit machine for software that doesn't understand long mode.

I hope that helps.

Thalaxis
10-08-2004, 07:09 PM
would 64bit support lead to better floating point performance during rendering? Or are double (64bit) floating point numbers avoided?
Yes, but it is due to the extra registers and the flat register model. The only relationship that those bear to being 64-bit is that they are not available in x86 compatibility mode, which for compatibility reasons only allows for 32-bit code.

Vertizor
10-08-2004, 07:53 PM
I guess IBM does it better than AMD then. Apple has already released 64-bit libraries for OSX 10.3, even though that OS is still a 32-bit OS. I'm just rehashing the marketing hype (which is bad practice, sorry) but apparently G5 Macs can run a 32-bit OS, execute 32-bit code, then turn around and execute 64-bit code.

lots
10-08-2004, 11:07 PM
Not quite. The catch is that x86-64 is a superset of x86-32. x86-64 has a mode that makes it look like a 32-bit machine, and 32-bit software is simply unaware of the extra stuff. However, if the OS is running in 32-bit mode, then the processor CANNOT switch to 64-bit mode. exactly :)

I guess IBM does it better than AMD then. Apple has already released 64-bit libraries for OSX 10.3, even though that OS is still a 32-bit OS. I'm just rehashing the marketing hype (which is bad practice, sorry) but apparently G5 Macs can run a 32-bit OS, execute 32-bit code, then turn around and execute 64-bit code. I'm browsing Apple's site, and can't find anything that confirms that. Everything I have found on running 64bit code and 32bit code in the same environment states that under Tiger (10.4) you will be able to take advantage of 64 and 32 bit code. Much like the x86-64 chips. This makes sense if you think about it. Since OSX is based on BSD derrivatives, I can imagine that it is only able to utilize what it was compiled on. Meaning since OSX is still 32bit, it can only run 32bit code at best. I'm fairly certain that the extended features on the G5 for 64bit will not be accessable to an OS that doesnt know its there. And since the OS is the one that arbitrates CPU time and functionality to "End user" applications, 64bit aware programs will not be able to run in this environment. Now the latest version of Panther may support some larger memory addressing, but from the info I have seen, it is not a fully 64bit OS. And thus, will not run native 64bit code. Its not really a manufacturer's problem more than the OS writer's problem (Apple and Mircrosoft).. The 64bit libraries being released may just be so developers can start compiling for 64bit 10.4.. but that's really just my assumption. I dont keep up too closely with Mac OS ;)

But I would bet that G5's 64bit capabilities are a super set of previous Mac processors at 32bits. Like x86-64 is to x86-32.

SpeccySteve
10-10-2004, 04:01 AM
And the price difference between a regular Athlon XP/MP vs. the 64-bit flavors is quite significant actually (the 64 bit ones being more expensive).
Not always the case, I was in urgent need of a decent cheap-ish cpu a while back and an Athy64 ( 754 socket) actually came in as cheaper than an equivalent 32-bit BartonXP chip at the time from most UK suppliers.

Vertizor
10-10-2004, 06:47 PM
Not always the case, I was in urgent need of a decent cheap-ish cpu a while back and an Athy64 ( 754 socket) actually came in as cheaper than an equivalent 32-bit BartonXP chip at the time from most UK suppliers.
My apology for neglecting the rest of the world :) Here in the states it appears that the 32 bit Athlons have taken the role of the "Durons" and similarly in pricing.

SpeccySteve
10-10-2004, 07:33 PM
This was a few months back though, so yeah, that's quite probably the case now, especially in the states.

Actually now I've checked , Overclockers UK are still selling the 3000 Barton for the same price as a 64 3000, well give or take a fiver. I suppose they still be able to shift them to folks who don't want a new mobo / memory etc.

lots
10-10-2004, 07:52 PM
Yeah.. In the states you can grab Athlon XP's for under 100 dollars, where the first speed grade of the Athlon64 is about 150 dollars..

Thalaxis
10-12-2004, 05:13 PM
exactly :)

I'm browsing Apple's site, and can't find anything that confirms that.


You won't, because it's not true. Without a 32-bit OS, you can't run 64-bit software. It would make no sense: the software would be able to address more memory than the memory manager.

But I would bet that G5's 64bit capabilities are a super set of previous Mac processors at 32bits. Like x86-64 is to x86-32.
The analogy is flawed, because x86-64 and x86-32 do not have an identical programming model, where as PPC does whether it's 32-bit or 64-bit. A better analogy would be that the G5 is to the G4 the same way that the P4 is to the PIII.

CGTalk Moderation
01-19-2006, 12:00 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.