# PC133

> speed rating of SDR SDRAM

**Wikidata**: [Q7118485](https://www.wikidata.org/wiki/Q7118485)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/PC133)  
**Source**: https://4ort.xyz/entity/pc133

## Summary  
PC133 is a speed rating standard for SDRAM (synchronous dynamic random-access memory), specifically denoting a peak data transfer rate of 133 MT/s (megatransfers per second). It belongs to the first generation of SDR SDRAM and was widely used in late 1990s computing systems to improve memory performance.  

## Key Facts  
- **Subclass of**: SDR SDRAM, the first generation of synchronous DRAM.  
- **Transfer Rate**: 133 MT/s (million transfers per second).  
- **Introduction**: Released in 1999 as an advancement over earlier standards like PC100.  
- **Peak Bandwidth**: 1.064 GB/s (gigabytes per second), calculated as \(133 \, \text{MT/s} \times 64 \, \text{bits} / 8\).  
- **Operating Voltage**: 3.3V, typical for SDR SDRAM modules.  
- **Compatibility**: Backward-compatible with PC100 systems but required optimized chipsets (e.g., Intel 440BX) for full performance.  
- **Wikipedia Coverage**: Documented in English, Arabic, and Spanish language editions.  

## FAQs  
### Q: What does "PC133" stand for?  
A: PC133 denotes a peak data transfer rate of 133 MT/s for SDR SDRAM modules, indicating their maximum speed capability.  

### Q: How does PC133 differ from earlier SDRAM standards like PC100?  
A: PC133 offers a 33% faster data transfer rate (133 MT/s vs. 100 MT/s), improving system performance for bandwidth-intensive applications.  

### Q: Is PC133 still used today?  
A: No, PC133 was largely phased out by DDR SDRAM and later memory technologies, which provided significantly higher speeds and efficiency.  

## Why It Matters  
PC133 played a critical role in addressing the growing demand for faster memory in late 1990s computing. By increasing the data transfer rate to 133 MT/s, it enabled smoother performance for applications like multimedia editing, 3D gaming, and early video streaming. As part of the SDR SDRAM family, PC133 represented a key evolutionary step in memory technology, bridging the gap between older asynchronous DRAM and modern DDR standards. Its adoption underscored the importance of memory bandwidth in overall system performance, driving advancements in processor and chipset design to fully utilize its capabilities.  

## Notable For  
- **Higher Transfer Rate**: 33% faster than the preceding PC100 standard, reducing memory bottlenecks.  
- **Backward Compatibility**: Could operate in slower systems (e.g., PC100) but required optimized hardware for peak performance.  
- **Peak Bandwidth Achievement**: Delivered up to 1.064 GB/s, a notable milestone for late 1990s memory technology.  
- **Adoption in Mainstream Systems**: Supported by popular chipsets like Intel’s 440BX, ensuring widespread use in consumer and business PCs.  

## Body  
### Overview  
PC133 is a speed rating for SDR SDRAM, the first generation of synchronous dynamic random-access memory. It specifies a maximum data transfer rate of 133 MT/s, achieved through improved circuit design and tighter timing controls compared to earlier standards.  

### Technical Specifications  
- **Clock Speed**: Operated at 133 MHz (megahertz).  
- **Bus Width**: 64-bit data bus, standard for SDR SDRAM.  
- **Latency**: Typical CAS (Column Address Strobe) latency of 3 cycles (CAS 3).  
- **Module Types**: Available in DIMM (Dual In-line Memory Module) form factors, commonly 168-pin for desktop use.  

### Historical Context  
- **Release**: Introduced in 1999 as a successor to PC100 (1997) and PC66 (1996).  
- **Market Impact**: Became a mainstream memory standard for systems using Intel’s Pentium III and AMD’s Athlon processors.  
- **Legacy**: Phased out by DDR SDRAM (2000), which doubled data transfers per clock cycle, rendering PC133 obsolete by the mid-2000s.  

### Applications  
- **Consumer PCs**: Used in gaming rigs and multimedia workstations requiring high memory bandwidth.  
- **Servers**: Deployed in entry-level servers for database and web hosting applications.  
- **Workstations**: Supported graphics and video editing workflows alongside early GPU accelerators.