The Pentium Pro was Intel’s next step beyond the Pentium. It had many innovations enabling it to outperform the plain jane Pentium. It ran at speeds from 150 to 200 MHz. It used a design innovation named Dynamic Execution. This was a kind of microarchitecture which is more advanced than the superscalar architecture of previous CPU’s. In general, this chip was able to handle more demanding applications and at faster speeds. It’s target audience was users of multi-processing systems, workstations and network servers.

PPro contained two separate 8KB L1 caches, one for data and one for instructions. Up to 1 MB of L2 cache could be addressed.

After release, some minor design flaws were found in the Pentium Pro. It was nicknamed the “flag erratum”. Design defects or errors are called errata. In short, the bug had to do with the conversion of floating point numbers to integers. When this conversion is impossible due to the range of the number, the hardware should respond with an exception value. The error is that the unit did not always return the exception value. This erratum affected the Pentium Pro and the Pentium II, but not the plain-jane Pentium or the Pentium MMX.

For more info on the flag erratum, check out Intel’s Flag Erratum Information.

Here is a list of Pentium Pro’s features, provided by Intel.

• Available at 150MHz, 166MHz, 180MHz and 200MHz core speeds
  
• Binary compatible with applications running on previous members of the Intel microprocessor family
  
• Optimized for 32-bit applications running on advanced 32-bit operating systems
  
• Dynamic Execution microarchitecture
  
• Single package includes Pentium® Pro processor CPU, cache and system bus interface
  
• Scalable up to four processors and 4 GB memory
  
• Separate dedicated external system bus, and dedicated internal full-speed cache bus
  
• 8K/8K separate data and instruction, non-blocking, level one cache
  
• Available with integrated 256 KB or 512 KB, non-blocking, level two cache on package
  
• Data integrity and reliability features include ECC, Fault Analysis/Recovery, and Functional Redundancy Checking
  
• Upgradable to a future OverDrive® Processor

Intel no longer provides a whole lot of information about Pentium Pro. The chip has been completely surpassed by more powerful desktop processors, and the Intel Xeon processor is now targeted at PPro’s former audience.