AMD HAS been banging the 64 bit drum for a bit now, especially when it comes to games. Starting with showing the beta of some Unreal flavour or another ported to the Hammer line over a year ago, they have been getting louder and louder. Sadly, while the game developers and the software support teams at AMD do understand what 64 bits can do, others don't.
The PR and advertising types are the culprits here, and part of the problem is that the general public is just as unaware. In addition to targeting the audience, they are part of it, and technically speaking, most of them breathe through their mouths. What is the problem? All those $#*&$^ ads that say 64 bits give you more FPS, or smoother gaming, or other technical minutia that are almost entirely in the realm of the graphics card anyway.
Even the AMD guide to benchmarking the Athlon64 line showed about a 0% improvement in frame rate for parts of 3DMark 2003 on a P4 vs an Athlon64. In the few, mostly older, games that show a difference, is the average user going to notice a jump from 320 to 340 FPS in Quake III? Does anyone still play Quake III? Speed is not the reason to choose a 64 bit processor for gaming.
The Athlon64 does bring a lot to the table in gaming, it is fast, but what it really buys you is worldspace. Back in the good old 8 bit days, the primitive wireframe 3Dish games that were around, and they were, had a world space that could be defined in a few large chunks. I really mean 'few'. Flying around, under the best of circumstances, you could wrap the world in a few minutes or less.
When the migration went to 32 bits, you could make the world bigger, or you could make it more detailed, but doing both was an exercise in compromises. If you didn't compromise much, the game used up memory like a Brit-hack uses free beer [Cough. Ed.]. Swapping ensues, and adequate performance becomes a distant memory.
64 bits has the potential to address this in 2 ways. The first is granularity. In a 32 bit number space, you can count to just over 4 billion, 4294967296 to be exact, or 4294967295 if you count from 0 like you really should. The 64 bit number space extends that to 18446744073709551616, which even the most casual observer will notice has a lot more digits. With the ability to map position things to the mm level, you get a worldspace of just over 4000km, not bad, but a little limiting if you are flying a plane, and woefully inadequate if you are in a spaceship needing to dock at anything other than a blobby thing with no discernable features. Jumping to 64 bit numbers for mapping, you can have both the mm accuracy, and a detailed space station. That is a huge advantage for anyone who gets annoyed by small, discrete levels that take forever to load. Think about an MMORPG where you can fit a much more detailed world into a single zone, and you are on the right track.
The other problem is memory. If you put a full world mapped to the mm level into 32 bit space, you will eat up more memory than a 32 bit CPU can address in anything larger than a split entrance ranch house map. Then comes the dreaded swapping, game pauses, and teed off players. While 2GB of RAM costs just over $300 now, that is as far as you can take a Windows box.
64 bit memory addressing lets you base memory capacity on your wallet. Even the most basic Athlon64 FX boards have 4 DIMM slots, leading to 8GB of memory if you feel like maxing your credit cards on 2GB DIMMs. No more swapping, or at least much less swapping.
At the Athlon64 launch, there were a ton of games, and a few game developers on display as well. With no offence meant to the Epic guys, I know it was a port, there was only one team who got it, and that was Crytek. Their game Far Cry was on display, and it used 64 bits right. The demo showed the usual lush island jungle with a MWABAG (Man With A Big *** Gun) running through it. Ho hum. It was very detailed, and smooth, as you would expect from a next generation game about to be released. You could see the leaves on the trees, and the level of detail showed clearly. Then they went into god mode and zoomed out. You could see the entire island, and you didn't lose any detail in the things up close. That is what 64 bit buys you when you 'get it'.
This is nothing you can't do with LoD mapping coupled with background loads, and various other cheats, but now you no longer have to. It works right, and you can put things where you want them, how you want them, and they still look right.
The down side is that they still take more memory than you can afford, but that is an economic problem, not a technical one. If I had to guess, I will go out on a limb and say that the cost of memory will come down to earth before the next three generations of graphics cards come out. They are the last bottleneck right now, a 64 bit world can hold more objects than a modern GPU can render.
Luckily, Nvidia and ATI are working hard on this, and with any luck will surprise us when the chips with names starting in four come out next year. With any luck, my Yule 2004 rant will be bitching about how those slacker TFT makers can't make a high rez monitor to save their lives.
[By Charlie Demerjian]
