PowerPC 740/750

The PowerPC 740 and 750 (codename Arthur)^[2] were introduced in late 1997 as an evolutionary replacement for the PowerPC 603e. Enhancements included a faster 60x system bus (66 MHz), larger L1 caches (32 KB instruction and 32 KB data), a second integer unit, an enhanced floating point unit, and higher core frequency. The 750 had support for an optional 256, 512 or 1024 KB external unified L2 cache. The cache controller and cache tags are on-die. The cache was accessed via a dedicated 64-bit bus.

The 740 and 750 added dynamic branch prediction and a 64-entry branch target instruction cache (BTIC). Dynamic branch prediction uses the recorded outcome of a branch stored in a 512-entry by 2-bit branch history table (BHT) to predict its outcome. The BTIC caches the first two instructions at a branch target.

The 740/750 models had 6.35 million transistors and were initially manufactured by IBM and Motorola in an aluminium based fabrication process. The die measured 67 mm² at 0.26 μm and it reached speeds of up to 366 MHz while consuming 7.3 W.

In 1999, IBM fabricated versions in a 0.20 μm process with copper interconnects, which increased the frequency up to 500 MHz and decreased power consumption to 6 W and the die size to 40 mm².

The 740 slightly outperformed the Pentium II while consuming far less power and with a smaller die. The off-die L2 cache of the 750 increased performance by approximately 30% in most situations. The design was so successful that it quickly surpassed the PowerPC 604e in integer performance, causing a planned 604 successor to be scrapped.

The PowerPC 740 is completely pin compatible with the older 603, allowing upgrades to the PowerBook 1400, 2400, and even a prototype PowerBook 500/G3. The 750 with its L2 cache bus required more pins and thus a different package, a 360-pin ball grid array (BGA).

The PowerPC 750 was used in many computers from Apple, including the original iMac.

PowerPC 745/755

Motorola revised the 740/750 design in 1998 and shrunk die size to 51 mm² thanks to a newer aluminium based fabrication at 0.22 μm. The speeds increased to up to 600 MHz. The 755 was used in some iBook models. After this model, Motorola chose not to keep developing the 750 processors in favour of their PowerPC 7400 processor and other cores.

PowerPC 750CX

IBM continued to develop the PowerPC 750 line and introduced the PowerPC 750CX (code-named Sidewinder) in 2000. It has a 256 KiB on-die L2 cache; this increased performance while reducing power consumption and complexity. At 400 MHz, it drew under 4 W. The 750CX had 20 million transistors including its L2 cache. It had a die size of 43 mm² through a 0.18 μm copper process. The 750CX was only used in one iMac and iBook revision.

PowerPC 750CXe

750CXe (codename Anaconda), introduced in 2001, is a minor revision of 750CX to increase its clock speed to 700 MHz and memory bus from 100 MHz to 133 MHz. The 750CXe also features improved floating-point performance over the 750CX.^[4] Several iBook models and the last G3-based iMac have this processor.

A cost reduced version of 750CXe, called 750CXr, has lower frequencies.

PowerPC 750FX

The 750FX (code-named Sahara) came in 2002 and increased frequency up to 900 MHz, the bus speed to 166 MHz and the on-die L2 cache to 512 KiB. It also featured a number of improvements to the memory subsystem: an enhanced and faster (200 MHz) 60x bus controller, a wider L2 cache bus, and the ability to lock parts of the L2 cache.^[4] It is manufactured using a 0.13 μm copper based fabrication with Low-K dielectric and Silicon on insulator technology. 750FX has 39 million transistors, a die size of 35 mm² and consumes less than 4 W at 800 MHz at typical loads. It was the last G3 type processor used by Apple (employed on the iBook G3).

A low powered version of 750FX is available called 750FL.

750FX powers NASA's Orion Multi-Purpose Crew Vehicle.^[5] Orion is using Honeywell International Inc. flight computer originally built for Boeing's 787 jet airliner.

PowerPC 750GX

750GX (codenamed Gobi), revealed in 2004, was a 7xx processor from IBM. It has an on-die 1 MB L2 cache, a top frequency of 1.1 GHz, and support for bus speeds up to 200 MHz among other enhancements compared to 750FX. It is manufactured using a 0.13 μm process with copper interconnects, low-K dielectric, and silicon on insulator technology. The 750GX has 44 million transistors, a die size of 52 mm² and consumes less than 9 W at 1 GHz at typical loads.

A low-power version of the 750GX is available, called the 750GL.

PowerPC 750VX

750VX (codenamed "Mojave") is a rumored, not confirmed and canceled version of the 7xx line. It would be the most powerful and featured version to date with up to 4MB of off die L3 cache, a 400Mhz DDR front side bus and the same implementation of AltiVec used in the PowerPC 970. It was expected to clock as high as 1.8 GHz (starting at 1.5 GHz) and reported to have additional pipeline stages, and advanced power management features.^[6] It was reported to be finished and ready for production in December 2003, but said timing was too late for it to get significant orders seeing Apple's iBook line had switched to G4s in October the same year, and thus it quickly fell off the roadmap. It was never released or heard from since.

There were follow up chips planned, such the 750VXe, which would have surpassed 2 GHz.

PowerPC 750CL

The 750CL is an evolved 750CXe, with speeds ranging from 400 MHz to 1 GHz with a system bus up to 240 MHz, L2 cache prefetch features and graphics related instructions have been added to improve performance. As the added graphics-related functions match closely the ones found in the Gekko processor it is very likely that the 750CL is a shrink of the same processor for general purpose use. The 750CL is manufactured using a 90 nm copper based fabrication with Low-K dielectric and Silicon on insulator technology and features 20 million transistors on a 16 mm² die. It draws up to 2.7 W at 600 MHz, 9.8 W at 1 GHz.^{[7] [8]}