Microsoft's newer, slimmer Xbox 360 250GB console is fast becoming old news, except that up until now, the software giant hasn't been particularly willing to detail the system-on-a-chip (SoC) that powers the device.
Details of the SoC were unveiled at the Hot Chips symposium yesterday, and it was there that Microsoft showed off the inner workings of the 45nm part produced by IBM and GlobalFoundries. Even if you're not a console gamer, you have to appreciate that this is essentially the first mass-market, desktop chip to squeeze a CPU, GPU, memory, and I/O logic onto a single unit.
Microsoft's new SoC boasts 372 million transistors, which would have been much more impressive five years ago when the Xbox 360 first debuted. The 45nm chip realizes a more than 60 percent power savings over the original 90nm chip from 2005 and measures 50 percent smaller.
One interesting thing about the new design is the inclusion of a "FSB Replacement" block. IBM/GlobalFoundries could have just connected the GPU and GPU with a low-latency internal connection, but doing so would have made the new Xbox 360 faster than previous versions. The FSB Replacement block actually adds latency to the mix and introduces a performance hit to keep the new model from outpacing older versions.