- Chapter 3: Microprocessor Types and Specifications
- Pre-PC Microprocessor History
- Processor Specifications
- SMM (Power Management)
- Superscalar Execution
- MMX Technology
- SSE (Streaming SIMD Extensions)
- 3DNow and Enhanced 3DNow
- Dynamic Execution
- Dual Independent Bus (DIB) Architecture
- Processor Manufacturing
- PGA Chip Packagingx
- Single Edge Contact (SEC) and Single Edge Processor (SEP) Packaging
- Processor Sockets and Slots
- Zero Insertion Force (ZIF) Sockets
- Processor Slots
- CPU Operating Voltages
- Heat and Cooling Problems
- Math Coprocessors (Floating-Point Units)
- Processor Bugs
- Processor Update Feature
- Processor Codenames
- Intel-Compatible Processors (AMD and Cyrix)
- P1 (086) First-Generation Processors
- P2 (286) Second-Generation Processors
- P3 (386) Third-Generation Processors
- P4 (486) Fourth-Generation Processors
- P5 (586) Fifth-Generation Processors
- Pseudo Fifth-Generation Processors
- Intel P6 (686) Sixth-Generation Processors
- Other Sixth-Generation Processors
- Itanium (P7/Merced) Seventh-Generation Processors
- Processor Upgrades
- Processor Troubleshooting Techniques
PGA Chip Packaging
PGA packaging has been the most common chip package used until recently. It was used starting with the 286 processor in the 1980s and is still used today for Pentium and Pentium Pro processors. PGA takes its name from the fact that the chip has a grid-like array of pins on the bottom of the package. PGA chips are inserted into sockets, which are often of a ZIF (Zero Insertion Force) design. A ZIF socket has a lever to allow for easy installation and removal of the chip.
Most Pentium processors use a variation on the regular PGA called SPGA (Staggered Pin Grid Array), where the pins are staggered on the underside of the chip rather than in standard rows and columns. This was done to move the pins closer together and decrease the overall size of the chip when a large number of pins is required. Figure 3.5 shows a Pentium Pro that uses the dual-pattern SPGA (on the right) next to an older Pentium 66 that uses the regular PGA. Note that the right half of the Pentium Pro shown here has additional pins staggered among the other rows and columns.
Figure 3.5 PGA on Pentium 66 (left) and dual-pattern SPGA on Pentium Pro (right).