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The PentiumTM Processor Q & A March 22, 1993 Background On March 22, Intel Corporation announced production shipments and technical details of its fifth-generation, compatible processor, the PentiumTM processor. Pentium processor-based system announcements will be made by computer manufacturers beginning in mid-May. General Q1. Which markets will be the first to employ Pentium processor-based systems? A1. We expect that initial customers for Pentium processor- based systems will be traditional early adopters who require increased performance to meet their needs. The Pentium processor will power advanced personal computers, workstations and super servers. Q2. I just bought an Intel486TM CPU-based system; is the Pentium processor going to obsolete it? A2. No. The Intel486TM CPU remains the mainstream processor. The Pentium processor will have limited availability in '93 and will be targeted at high-end applications, such as servers. As we have seen with the Intel486 CPU, the Pentium processor will evolve downward in the market and one day become the volume mainstream processor . Speed/Performance Q3. What is the performance of the Pentium processor in comparison to an Intel486 CPU? A3. The Pentium processor runs applications up to five times as fast as the popular, desktop-standard 33-MHz Intel486 DX CPU. The 66-MHz Pentium processor operates at 112 million instuctions per second Dhrystone (MIPS), it has a SPECint92 rating of 64.5 and SPECfp92 rating of 56.9 and an Intel iCOMPTM Index rating of 567. The performance delta between the 66- and 60-MHz version of the Pentium processor is about 10 percent. Intel/Page 2 Pentium processor Q4. What is the performance of the Pentium processor in comparison to RISC machines? A4. The Pentium processor has equal or greater integer performance (SPECint92) than all current volume shipping RISC-based systems. In addition, the Pentium processor has demonstrated workstation-class floating- point performance. The RISC processors available today are designed to be a very high-end processors. In the mainstream volume workstation and PC marketplace, it is important to be able to ship millions of processors, not just thousands. Q5. What is the iCOMPTM Index? A5. The iCOMPTM Index was created by Intel as an easy-to-use index to give PC buyers useful processor performance information when selecting an Intel-based PC. This tool reflects the performance of the microprocessor and should not be used as a measurement of overall system performance. For example, the Intel486 SX CPU at 25-MHz has an iCOMP rating of 100, the Intel486 DX2 CPU at 66-MHz has an iCOMP rating of 297 and the Pentium processor at 66-MHz has an iCOMP rating of 567. Naming Q6. Why did you name it the Pentium processor? A6. The purpose of naming it the Pentium processor is to help users recognize the genuine Intel processor. Imitators sell products using the "386" and "486" designation when the products are not on par with Intel's. We want to ensure that the PC user knows which processor is the genuine Intel chip. The Pentium name will designate that: no one else can legally use that name. Upgradability Q7. I have heard people refer to Pentium Ready or OverDriveTM Pentium systems. What are they and when will they be available? A7. Many Intel486 DX2 CPU-based systems will be upgradable to Pentium processor technology. Whether systems are upgradable is based on system design considerations. The Pentium processor-based OverDriveTM Processor will be introduced in 1994. Intel/Page 3 Pentium processor Software Q8. What applications are best suited for Pentium processor- based machines? A8. The Pentium processor will enable high-performance servers at a lower cost than currently available. The Pentium processor is capable of running all major network operating systems with scalability from the desktop to the data center. Performance-intensive desktop and technical applications, such as imaging, real-time video and voice recognition will benefit from the increased performance available from the Pentium processor. In addition, it will expand the acceptance of Intel processor-based systems into applications such as scientific modeling, computer-aided design/engineering (CAD/CAE), large-scale financial analysis and high- throughput client/server applications. Q9. Will software written for 286/386/486 CPU-based systems run on the Pentium processor? What will be the difference? A9. Yes, Intel has always been committed to compatibility across processor generations and that will continue. To achieve the highest possible software application performance from Pentium processor and Intel486 CPU- based systems, software can be optimized. Q10. What is software optimization? A10. Optimization is the process by which operating systems and application software are developed or recompiled to take full advantage of the Intel architecture. Results are most dramatic on the Intel486 and Pentium processor- based systems. Q11. How much faster can the Pentium processor run today's software than the Intel486 DX2 CPU? A11. About 40-70% faster than the 66-MHz Intel486 DX2 CPU running existing software. Intel/Page 4 Pentium processor Q12. Which software developers have committed to optimizing their applications for the Intel architecture? A12. Currently, Andersen Consulting*, Adobe*, Aldus*, Autodesk*, Cadre*, Calera*, ComputerVision*, Dragon*, EDS*, Frame Technology*, Gain Technology*, Gupta*, Hypercube*, IBM*, Ithaca*, Interleaf*, Knowledgeware*, Kurzweil*, Lotus*, Microsoft*, Novell*, NCR*, Oracle*, Pixar*, Reuters*, SAS*, SCO*, Set Technology*, Sigma Design*, SunSoft*, Sybase*, Univel*, Viewlogic*, Ventura* Software, and Wolfram* have all committed that one or more of their applications will be optimized for the Intel architecture. More software companies are committing every week. Q13. Which operating system suppliers are committed to supporting Pentium processor? When? A13. IBM*, Microsoft*, NeXT*, Novell*, SCO*, SunSoft*, Univel* and USL*. You will need to check with them on announcement plans or ship schedules. Q14. Which compiler and tools companies are supplying optimized tools and compilers? A14. Absoft*, Borland*, IBM*, Liant*, MetaWare*, Micro Focus*, Microsoft*, NeXT*, SCO*, USL*, and WATCOM*. Q15. If Pentium processor performance is so great, why would I want or need to optimize my software? A15. While the Pentium processor is significantly more powerful than its predecessors, performance can be enhanced when software is optimized for the Intel architecture. Intel has been working with its software partners for over a year to ensure that full advantage of the Pentium processor and Intel486 microprocessor performance can be taken by tools, compilers, operating systems and application software. Q16. How much incremental performance can I expect from an optimized application running on a Pentium processor- based system? A16. Performance enhancements will vary, but early optimization projects have yielded up to 30% performance enhancement over the enhancement provided by the chip alone. Intel/Page 5 Pentium processor Technical Details Q17. How does the Pentium processor differ from the Intel486 CPU? What are new features of the Pentium processor? A17. The Pentium processor includes both new architectural features as well as enhancements to the Intel486 CPU. New architectural features are superscalar architecture, a totally redesigned Floating Point Unit (FPU), branch prediction, separate code and data caches, a write back cache with MESI (Mutual Exclusive Shared Invalid) protocol, multiprocessor support and built-in data integrity for increased reliability. Other enhancements to the architecture include hardwired instructions, enhanced microcode, increased page size, 64-bit data bus and pipelining. Q18. What is superscalar? A18. Superscalar is new to the Pentium processor and is a microarchitecture design technique that allows multiple instructions to be executed simultaneously on chip. (An anology: superscalar is like adding another lane to a single lane highway; more cars (instructions) can go to the same place at the same time). Q19. What is branch prediction? A19. Branch prediction is new to the Pentium processor and is another performance improvement technique. Since software execution incurs substantial delays on branches, points in the software instruction stream require a branch to a new, non-contiguous location in system memory to fetch the next instruction. This Intel-developed technology will predict where the program is going next and can actually begin working on the next instruction before it is actually called upon. Q20. Why do you have separate data and instruction (code) caches? A20. Having the two separate caches allows the CPU to fetch data and code in parallel, doubling the available cache bandwidth. In addition, the Pentium processor has very large on-chip data paths, some as large as 256 bits. The data cache is dual access, meaning two instructions can read and write data in parallel. This complements the superscalar design (dual pipeline). * Trademarks are the property of their respective owners. Pentium, Intel486 and iCOMP are trademarks of Intel Corporation.


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