According to IBM and Microprocessor Forum literature, IBM plans to announce a new G3 processor on Wednesday at the Microprocessor Forum in San Jose, CA. Officially named the 750FX, this new G3 is intended to be a further improvement in power consumption, performance and price over the IBM 750CX and 750CXe processors announced early this year at the Embedded Processor Forum. The 750CX and 750CXe processors have been targeted to the embedded processor markets successfully, but Apple also uses them in current iBook and iMac designs. IBM is targeting the 750FX at the embedded market as well, but the announcement at the Microprocessor Forum suggests that IBM intends this processor for both the desktop and the embedded markets.
The 750FX is being called the successor to the 750CX and 750CXe. The 750CX and 750CXe designs have an on-die cache — this feature was one of the goals of their design. The cache is smaller — 256KB as opposed to 1MB on earlier G3s, but it runs at the same speed as the processor. More importantly for IBM, having the cache on the processor die allows them to design the chip without the external cache connections. This allows IBM to package the chip more easily and ultimately sell the processors at a lower price. The 750FX is expected to continue this strategy.
According to IBM’s PowerPC strategic roadmap, their next PowerPC processors will top out at over 1GHz. The current IBM leader is the 750CXe, which is sold at speeds of 400MHz to 700MHz. Obviously, the 750FX will exceed this, but MacCentral’s sources will not confirm the 700MHz to 1GHz range that has been recently reported.
Also according to the roadmap, IBM is expected to switch to a 0.13-micron Low-K Dielectric copper manufacturing process with the next generation. The 750CX and 750CXe currently use a 0.18-micron copper manufacturing process, and these processors were the first 750s to use that — earlier G3s used a .22-micron copper manufacturing process. For those not steeped in processor details, a smaller manufacturing process allows processors to have more transistors (for more processing power) and to operate at lower power levels and higher frequencies.
The 750FX is a likely candidate for IBM’s latest manufacturing advances, as the 750CX and 750CXe showcased IBM’s manufacturing technology prowess. IBM’s roadmap introduces new manufacturing technologies with each generation. Earlier this year IBM began shipping processors using SOI (Silicon On Insulator) to further enhance performance and reduce power consumption. The next technology that IBM intends to implement, according to the roadmap, is Low-K Dielectric. This is the addition of a nonconductive shielding substance to the processor that prevents the tiny, closely packed together wires on a processor from electrically interfering with one another. This should further reduce power consumption and heat generation and should allow processors using it to operate at an even higher frequency.
Finally, IBM publicly said that the 750FX would feature improved bus utilization, memory management and reliability.