IBM RS64

The IBM RS64 is a 64 -bit processor family, which was used in the late 1990s in IBM's RS/6000 and AS/400 servers.

Cobra and Muskie

The Cobra or A10 processor, IBM introduced in 1995 with a clock frequency 50-77 MHz. This single-chip CPU found its use in the AS/400 and was produced in 0.6 micron aluminum process.

A year later, IBM introduced the multi-chip CPU Muski (also known as A25 or A30) before. This 4- way SMP CPU running at a clock frequency of 125-154 MHz and was used in AS/400. It was made in the BiCMOS process.

RS64

The RS64 or Apache was introduced in 1997 and was intended for the RS/6000 and AS/400 servers. This CPU runs at a clock frequency of 125 MHz, has an integrated 128 -KB L1 cache and an external 4 MB L2 cache. The L2 cache is connected to a 128 -bit wide bus with the CPU and runs at full clock rate. Was made ​​of the RS64 in the BiCMOS process.

RS64 - II

The RS64 -II or North Star was introduced in 1998 with a clock frequency of 262 MHz and an 8 MB L2 cache. The L2 cache running at full clock speed and is connected via a 256 bit wide 6XX bus (see PowerPC 620 and POWER 3). The CPU consists of 12.5 million transistors, which are housed on one die with an area of ​​162 mm ². The RS64 - II had the designation A50 in AS/400.

RS64 - III

The RS64 - III or Pulsar was presented with a clock frequency of 450 MHz in 1999. The biggest change to the architecture was enlarged to 128 KB L1 cache ( data cache and instruction cache ). In addition, the accuracy of branch prediction has been improved (Branch Prediction). Even with a failed branch prediction, this processor only needs a maximum of one more cycle. Other parts of the CPU are the five-stage pipeline and connected with a 256 -bit wide bus L2 cache with a size of 8 MB. The maximum data transfer rate of the cache is 14.4 GB / s with 225 MHz clocked SRAM.

On the 140 mm ² of the RS64 - III 34 million transistors are housed. It was produced in CMOS 7S process.

In 2000, IBM introduced under the name of Istar before another version of the RS64 -III. The only difference was the SOI manufacturing process, whereby the clock frequency could be increased to 600 MHz.

RS64 -IV

In 2000, we introduced the 600 MHz before (later 750 MHz) clocked RS64 -IV or sstar. This CPU had a up to 16 MB of L2 cache and was the first processor for the mass market who supported multithreading. The processor consists of 44 million transistors ² are housed a 128 mm. It was produced in a 0.18 micron process.

• IBM processor