If you’re trying to find information on the NVIDIA 9400M Apple is adding to its lower-end MacBooks, here’s a hint: it doesn’t exist. (Not literally, anyway.)

Plain-English summary: NVIDIA’s new graphics card architecture used on the MacBooks combines a chip on the CPU (as found on the old MacBooks) with a dedicated GPU (as found on the MacBook Pros). The dedicated, “discrete” chip is designed for lightweight, power-efficient use, but it should be a boost from the old model. “9400M” applies to both those chips, which have … uh, different numbers. The problem is, no one knows exactly how the combination will perform until they test it; we expect to have more from live visual developers soon.

Updated: Actually, it seems “9400M” on the Mac refers to a new, single-die chip that NVIDIA considers equivalent to their two-chip (discrete + dedicated) combination with the same brand name 9400M. An anonymous reader points us here:
GeForce 9400M G

That last “G” apparently refers to this being a single-chip, motherboard graphics solution. Remove the “G”, and you have a different (though similar), two-chip motherboard + discrete solution. Both seem to have 16 stream processors total, even though the 9400M not on the Mac splits it across two other chips. (Confused yet?) As if it weren’t hard enough to follow whether that “G” is there or not, Apple calls the 9400M G the 9400M. So that means a lot of what I say here refers to the 9400M as on PCs, not the 9400M as on Macs. Ugh.

The information on the site above was added since I first posted this story. Update coming soon, though I’m going to sort my facts first, as this is not exactly Great Moments in Lucid Branding.

Exact details: Yes, as a bizarre twist of branding, the “9400M” is just a brand applied to the combination of two other GPUs. Put a GeForce 9100M G on your motherboard, and add either (bizarrely) a 9300M GS or or 9200M GS as the discrete GPU, and you get a 9400M. What’s the difference between the 9300M and the 9200M (aside from, uh, “100″)? Only the 9300M GS supports hybrid SLI (a technology for combining the two GPUs for better power/performance balance), and Blu-Ray playback.

And that brings us more questions than answers — some questions that are answered for Windows users, but even some questions for them, too (like real-world performance):

If you haven’t seen it yet, Jamie and Adam did what may be the greatest illustration of a computing concept onstage ever, using an 1100-barrel paintball gun:

Updated: We’ve seen the basic idea before — one of the Max/MSP + Atmel-powered Printball notes his own, similar project, as featured on Pixelsumo way back in 2005. But it’s the first time I’ve seen this used to illustrate this point.

The basic idea: GPUs, by using parallel processing, are able to render graphics more effectively than CPUs. And while the illustration is something of an oversimplification, it is pretty literal in terms of showing people what’s going on — and why GPUs are uniquely well-suited to computing graphics. Conceptually, it’s really one of the most brilliant demos I’ve ever seen.

There are just a couple of problems — and, amusingly, this demo makes them visible, as well.