May 16th, 3pm PST: PS3 Launches. May 16th, 6pm PST: Xbox2 Launches

[Drake Tungsten]

Did any of that article even make sense to most people who read it?

The middle was a bit dodgy. I thought I got the gist of it, though.

By the way, at what point can we declare the Gamecube dead?

After the next Zelda comes out...

[Nostromo]

Originally posted by Asher
Did any of that article even make sense to most people who read it?

I admit, I skipped most of it and jumped right at the conclusion

[Asher]

I think the gist of it is:

Typical PC processor:


Xbox 360 CPU:

[Drake Tungsten]

Yep. Thank god for pictures!

[MrFun]

Actually, thank God for Asher -- the technology messiah.

[Drake Tungsten]

nostromo linked to the article...

[Asher]

There's already a 6-page thread on this article on Beyond3D if anyone's masochistic and wants more tech detail/debate: http://www.beyond3d.com/forum/viewtopic.php?t=23615

A lot of those posters are people in the industry. Off the top of my head, ERP, Fafalada, DemoCoder, Gubbi, and nAo work for game development companies. Most of them don't mention publically, but they give a lot of interesting feedback regarding the powers of current-gen and next-gen consoles based on the information they've been given, and their real-world experience.

[Asher]

Originally posted by Drake Tungsten


nostromo linked to the article...

I thought the article would be too technical to be useful to most people on Poly. The first one was more higher-level.

[MrFun]

Originally posted by Drake Tungsten


nostromo linked to the article...

And Asher explained it better.

[Drake Tungsten]

I thought the article would be too technical to be useful to most people on Poly. The first one was more higher-level.

I'm not criticizing. Just wondering why MrFun is giving you the credit.

And Asher explained it better.

By posting pictures from the article?

[MrFun]

But what counts is that Asher provided pretty, colorful pictures!!

[Nostromo]

That's why I quoted the conclusion. It sums it up nicely and its easy to understand.

[Asher]

I can provide a synopsis though.

Xenon (the Xbox 360 CPU) took 3 modern IBM processors, removed some functionality, added other functionality on top of it. The removed functionality was what's called Out Of Order Execution (OOOE), which basically means the chip itself decides in real-time what order the CPU instructions should go into, to attempt to optimize performance. That takes up a lot of "real estate"/transistors to do, not to mention additional power/heat concerns, so they were removed. Now it's an "In Order" chip, so the chip simply processes instructions as they're given.

The burden is now on the compiler (the tool that translates high-level C/C++ code into machine code) to optimize that correctly. You can't really do this on the PC, because there's many different processors and each one behaves differently. Since the console hardware is fixed and unchanged, developers know exactly how the customer's CPU is going to behave, so they can properly order the instructions optimally.

Each processing core has 2 "VMX" units, which are IBM "vector" units. Vector units work with a principle called SIMD (Single Instruction, Multiple Data) to efficiently work on matrices. This kind of operation is extremely common in 3D graphics in particular. There are 128 128-bit registers available to each thread (a thread is a string of CPU instructions...there are two per core, so 6 total on the whole CPU). So, for example, you could use it to store a 4 dimentional matrix with 4 32-bit values. If you wanted to, say, calculate the inverse of that matrix, you can do it with a single instruction with SIMD. It understands that all of the numbers are associated. In regular computation, you'd need to write code to do that all by hand, which is many more instructions.

Or even more simple...if you wanted to multiply each number in the matrix by 2, it's 1 instruction in SIMD and 4 instructions in the oldschool way. So it's more efficient for matrix operations.

The article touches on "branches"...those are simply conditional statements -- paths the code can take. 3D graphics don't usually have branches...it's what's called dumb code, it's all straightforward. You can do these in SIMD-type units easily.

The problem is when you have branching code, like artificial intelligence (think of all of the conditional logic in AI) or even physics (all of the objects should be able to interact with eachother, so it's not predictable), it's extremely difficult to make these "parallel" instead of "serial". For example, running AI across two threads instead of one. Usually the AIs need to talk to eachother, which complicates things immensely.

That's something that's required in the Xbox 360 -- making everything parallel. Each core is individually weaker than the standard PC processor, the power is in getting them all to work, and work efficiently. To do that, Game Developers will need to figure out how to make their games use 6 threads...when they're used to 1 thread on the PC and current-generation consoles.

The situation is worse on the PS3, with its "Cell" processor. It only has 1 of the cores in the Xbox 360 (and it's even slightly less powerful than an Xbox 360 core), and the rest of the 7 "SPE" chips are really just dumb vector processors. They don't handle branching code at all really, which means you've got just 1 chip to do a lot of stuff..and probably a lot of spare vector processing power. It seems imbalanced to me, and a non-optimal solution...but this is Sony's Plan B.

Anyhoo, probably confused everyone more. I tried...

[Asher]

As a point of interest, I work on the IBM PowerPC compiler that literally everyone is using now.

As development is picking up on Xbox 360, and to a lesser extent PS3, we're getting swamped with customer questions.

No developers have started with Revolution development...

[Asher]

Info on the PS3:

Sony confirms they're targeting a Spring 2006 launch date for the PS3, possible simultaneously launching in Japan (but not Europe). http://www.gamespot.com/news/2005/06...s_6126832.html

But most analysts are saying a Fall 2006 is most likely for the US, given that parts such as the PS3's graphics chip actually aren't even finished yet.

Also, looks like the PS3 will ship without a harddrive by default (like the PS2 did). This means that, unlike the Xbox/Xbox 360, devs cannot assume one exists and use it for things such as caching. :/