32 bitties vs 64 bitties and CMx2

[Bammer]

I just watched a show on BBC World and they were asking 'true' experts about 32 bit cpus and 64 bit cpus and the future.

Currently, 64 bits are out and Intel states they will not produce one. AMD has the market sewn up it seems.

What do u people 64 bit cpus will have on future desktop computers ?

When will we make the switch ?

How will it affect the CMx2 engine ? Will it even work in a 64 bit environment ?

Here is the article:

http://www.bbcworld.com/content/template_clickonline.asp?pageid=666&co_pageid=2

[-hero-]

Not that it's even relevant at all, since there's no 64-bit version of Windows for AMD yet anyway, but what possible benefits could one obtain for purposes of gaming at this point? 64-bit addressing has potential down the line, but certainly not right now, not for consumers anyway.

This is not to say the new AMD gear isn't any good, only that there's no point in hypothesizing ostensible benefits of 64-bit OSes and CPU architectures for gaming at this point in their development.

[Bammer]

Originally posted by -hero-:

Not that it's even relevant at all, since there's no 64-bit version of Windows for AMD yet anyway, but what possible benefits could one obtain for purposes of gaming at this point? 64-bit addressing has potential down the line, but certainly not right now, not for consumers anyway.

This is not to say the new AMD gear isn't any good, only that there's no point in hypothesizing ostensible benefits of 64-bit OSes and CPU architectures for gaming at this point in their development.

Hi,

CMx2 is still a long way off, by then we may be switching over to 64 bit cpus. My next upgrade is 'unlikely' to be a 32 bit cpu, as I know their life expectancy is now limited. Windows is coming out with an operating system for 64 bit systsms soon.

Once it does programers for the higher end games like Quake etc., WILL push the limit, as is the norm.

Food for thought

[Berlichtingen]

Originally posted by Bammer:

Will it even work in a 64 bit environment ?

THe G5 processor is 64 bit, and G5s will run any 32bit app that can be run in OSX or Classic. Therefore, I don't see why the next engine wouldn't run on a 64bit machine. This, of course, assumes that Microsoft doesn't screw up their next rev OS... er, I guess you Windows users are screwed

[Schrullenhaft]

Intel does have a 64-bit processor - it's called the Itanium. It's a joint venture between Intel and HP and it's based on HP's PA-RISC architecure rather than any x86 core Intel has made. Intel's CPU is made to run only 64-bit code since it does an absolutely horrible job with 32-bit code (the performance drops incredibly - at least last I heard it did). AMD's advantage was that their 64-bit processor ran 32-bit code at a good speed, so it handles mixed 64-bit and 32-bit programs fairly well - a definite advantage when it comes to those early adopters of 64-bit OSes and programs.

64-bit CPUs have actually been around for awhile, but you usually see them on Sun hardware or other UNIX workstations or servers.

A 64-bit version of Windows will be limited to 'Server' versions for the time being when they come out and they probably won't be 'performance champs' for quite awhile as Microsoft converts all of the code to 64-bit (uh... I'm not actually sure what Microsoft's strategy is for 64-bit Windows).

Basically, as mentioned above, the biggest advantage for 64-bit CPUs is the ability to address more than 4Gb of memory (which is the theoretical limit for Intel Pentiums and AMD Athlons - 2 to the 32nd power). Additional memory is basically useful for databases, server functions, very large CAD or animation projects, etc. Most desktop users (including gamers) will probably have little use for the larger amounts of memory that 64-bit CPUs can address. Of course Microsoft will attempt to rectify this by increasing the memory requirements of Windows ("I'm sorry, but you must have 1Gb of RAM to boot into Windows...").

Anyway... I doubt that CMx2 will be written specifically for 64-bit processors. 32-bit processors and OSes will still be the majority for the next 3 years (the G5 and its successors notwithstanding). It will be interesting to see what changes Apple makes to OS X for the G5. I assume the G5's mixed-mode performance is pretty good, so there won't be too much of a rush to do this.

[Redwolf]

Actually the address space limit for current 32-bit CPUs is 3 GB since OS kernels reserve the upper 1 GB. This is one direct advantage of the AMD-64 even if it runs a 32 bit program. The 32 bit program can use the full 4 GB (since the kernel is 64 bits and doesn't have to live in the lower 4 GB with the application).

In general, games tend to be very tight, efficient code that only loads what they actually need. More than 3 or 4 GB address space is usually required for applications which have giga-bytes of data which all gets mmap'ed to be potentially used, but isn't used. A game usually does a finer-graded job of data loading.

The point about the Itanium is that it is a full SIMD architecture. It can execute several code paths in parallel, but only when the assembly code has been written to do it. In the Itanium there is no "automatic" parallelism as in current CPUs. Current CPUs execute normal code with a given level of parallelism by figuring out some independence in the normal code flow on their own (they are "superscalar"). The Itanium drops the attempt to figure it out automatically, but now you have to specify it yourself. "You" is usually not you the programmer but your compiler.

In practice however it is incredibly hard to write a compiler which does a good job on auto-parallelizing normally written C or C++ code. These languages are just not meant for it, they allow too much freedom where the compiler cannot figure all dependencies out. The strength of the Itanium is that it has a large number of parallel engines. But each one of these engines is slower than one of the (fewer) superscalar engines in current CPUs. If you don't feed the Itanium with already parallelized code you lose big.

32-bit IA-32 code on an Itanium always use just one engine so performance is lousy until maybe Intel puts in a superscalar engine in addition (which would be double effort).

So far I only heard people throwing up on writing good compilers for SIMD architectures. Intel is spending enormous amounts of money on writing compilers but it doesn't look to promising. For now, the Itanium's advantages are mostly limited to programs which can make heavy use of predefined, hand-optimized libraries and/or are written in Fortran.

The only hope I have for a high-level language is Lisp. Because the Lisp compiler writer can pass the task of identifying parallel code paths up to the programmer. The Lisp language can be transparently changed with new control constructs to allow the programmer to specify the parallel items. How many programmer would like to do that is a different matter, somehow I don't see Lisp taking over the world because of the Itanium.

It's hard to believe but I'm slowly getting convinced AMD will actually win this fight. Too bad, I would have like to sit around 10 years writing a SIMD Lisp compiler

[argie]

Originally posted by Schrullenhaft:

I assume the G5's mixed-mode performance is pretty good, so there won't be too much of a rush to do this.

Well, Panther (64 bits OS) is scheduled to be released in 11 days from now.

[Bammer]

Strange, I would have thought 64 bits would have allowed programmers more opportunity to increase the power of their software script.

More power, more capabilities in the game.

Let us take this example:

BFC keeps infanctry in platoon to company level. If there was a 64 bit CPU and 513 mg videi card and a 1 GB of ram I would think that they could have individual soldiers displayed at least in samller battles.

What do others think ?

[rune]

From Tom's Hardware

Merely looking to the installed hardware foundation, on the other hand, brings no benefits. The software has to be completely readjusted to achieve speed advantages in applications running under Windows XP 64. Whether the manufacturer will do this any time soon is rather doubtful.

Why? Because if you code a game, you would need two complete different versions. I don't see this happening yet.

Rune

[Redwolf]

Well, 64 bits bring no speed advantage at all, on the contrary the bigger pointers and -if you use them- the bigger default integers increase the memory footprint. Memory bandwidth and cache utilization drop and if you are unlucky you get into virtual memory paging.

The speed advantage of a 64 bit program only comes into play if you can use the bigger pointers to avoid having to shift around data in the 3 GB you normally have, or if you have to use integers bigger than 32 bits (which you would have to emulate using some pair of integers, bignums or floating point, whatever fits your needs).

That applies to a CPU like the AMD-64 which uses the same hardware to execute 32 and 64 bit programs.

On a CPU like the Itanium where 32-bit programs are executed on a second-class additional unit all bets are off.

Moderate exceptions apply ever under AMD-64, for example, you have more registers for a 64 bit program. On the other hand, besides bigger data types code for AMD-64 bit programs is also bigger because of the prefix arguments.

[Redwolf]

Originally posted by Bammer:

Let us take this example:

BFC keeps infanctry in platoon to company level. If there was a 64 bit CPU and 513 mg videi card and a 1 GB of ram I would think that they could have individual soldiers displayed at least in samller battles.

Sorry, that is an inncorrect example.

1 GB of RAM + 513(?) MB of video RAM can be addressed with a 32 bit CPU. No reason to go 64 bits.

Now current hardware can already display 12 soldiers instead of 3. The 3 soldiers were acceptable three years ago when CMBO came out, the average machine got 4 times as powerful since then (Moore's law), the video cards even more. 12 soldiers would take 4 times as much polygons to draw, but not 4 times as many textures to hold, so the increased load would be even lighter.

But BFC would have to program that stuff, figure out how to make gestures work. Most importantly, it would be boring if all 10 would always do the same. Individual placement would take a long time to program so that it looks convincingly.

Also, I am sure there are plenty of people who are glad they can play CMBB and CMAK on their old rig. Remember the economy sucks and not everybody's life priority is to play Unreal Tournament.

[Bammer]

Originally posted by redwolf:

Sorry, that is an inncorrect example.

1 GB of RAM + 513(?) MB of video RAM can be addressed with a 32 bit CPU. No reason to go 64 bits.

Now current hardware can already display 12 soldiers instead of 3. The 3 soldiers were acceptable three years ago when CMBO came out, the average machine got 4 times as powerful since then (Moore's law), the video cards even more. 12 soldiers would take 4 times as much polygons to draw, but not 4 times as many textures to hold, so the increased load would be even lighter./QB]

Hello,

If we were to apply your logic, why don't we all just go back to TRS-80s

Software programers are only limited by the hardware that drives it ! The better the hardware the stronger the software that can be written.

I think 64 cpus are just around the corner for desktops and correspondingly stronger programs in the very near future.

Keep an eye on the graphics leaders like Quake, they will be our canaries ! And programs like CM will soon follows Perhaps, it will be called the CMX3 engine

[-hero-]

I think 64 cpus are just around the corner for desktops and correspondingly stronger programs in the very near future.

But the point is, you can get those on your desktop now and yet they have very specific application environments in which that capability is actually useful.

I've sold and used some of the HP ZX-series Itanium2 workstations and CPU for CPU they're the fastest things on the planet...if you're trying to do structural or crash analysis with ANSYS or NASTRAN. But what gaming code on the horizon is going to make use of 64-bit environments? Is Excel going to run any better with 64-bits?

You're going to be hard-pressed to find those consumer-level applications. So let's not expect 32-bit systems to be relics at this time next year.

[aka_tom_w]

Originally posted by Ariel:

</font><blockquote>quote:</font><hr />Originally posted by Schrullenhaft:

I assume the G5's mixed-mode performance is pretty good, so there won't be too much of a rush to do this.

Well, Panther (64 bits OS) is scheduled to be released in 11 days from now. </font>

[Bruceov]

Dont make the game run on some esoteric technologythat will cost the user thousands of dollars from what they have now.

[Redwolf]

Originally posted by Bammer:

If we were to apply your logic, why don't we all just go back to TRS-80s

Software programers are only limited by the hardware that drives it ! The better the hardware the stronger the software that can be written.

Yes, because the TRS-80 had 64 KB directly addressable without tricks.

This is arguably not enough for CM, so that's why we don't go back (and the lack of a MMU and FPU, besides speed).

64 bits will be needed when our applications make use of more than 3 GB virtual(!) memory. For a number of applications, even for home use, that is already approaching.

However, and that is my original point, a graphically or computational intensive game always has a smaller footprint than a comparable desktop application (fromt he same generation). The game designer cannot effort to be generously about memory compactness.

That is why generations of CM engines will always have less demand for 64 bits (and 128 bits after that) and will not move to it earlier than other applications.

[Bruceov]

It dcoesn't matter how good the game looks if we have to upgrade our systems to play the game it will cost you many sales

[Esper]

2005 will probably be the earlist you begin to see 64 bit programs coming, particularly games. Even then, many companies will probably continue to make 32 bit until 2007-9. Intel has made a 64bit processor for years. We have serveral itaniums(Intels 64bit) at work. And there is a 64bit version of windows. I don't see why people are wetting themselves over them. I remember all this hype when Duel procs was all of a sudden the cool thing and the wave of the future years ago.. how many games have been designed for duel proc machines? The 64bits will be nice but I wouldn't run out and buy one right now or anytime soon unless you just want the cool factor of saying you have one.