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2/6: CPUs & Memory. CPUs Parts of a sample CPU Types of CPUs available ROM RAM different kinds & uses inc. VRAM, SRAM. image courtesy of How Computers Work CD. The CPU. CPU terms capacity, -bit clock speed, MHz CISC, RISC CPU brands & models. image courtesy of AMD.com.
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2/6: CPUs & Memory • CPUs • Parts of a sample CPU • Types of CPUs available • ROM • RAM • different kinds & uses inc. VRAM, SRAM image courtesy of How Computers Work CD
The CPU • CPU terms • capacity, -bit • clock speed, MHz • CISC, RISC • CPU brands & models image courtesy of AMD.com
CPU: Central Processing Unit • The Microprocessor or CPU (Central Processing Unit) is the “brains” of the computer. • All other components (RAM, monitor, disk drive) act like bridges to link you & the processor. image courtesy of AMD.com
Coprocessors • Coprocessors are also in PC’s. • They handle functions like graphics, 3-D acceleration, and sound cards. • Help reduce the load on the main processor. image courtesy of How Computers Work
Data Capacity • refers to the amount of data that the processor can process at one time. If a number is bigger than what the processor can handle, it breaks it down into manageable parts, processes it, and puts it back together. • 8 bit processor: handles numbers up to 8 bits long (2 to the 8th power: 256) • 16 bit processors handle numbers up to 2 to the 16th power or 65,536) • 32, 64 bit processing (etc.)
Clock Speed • Timer that everything in the processor uses as a pacesetter. • Measured in MegaHertz (millions of cycles per second) • Same model of processors can have their clock speeds compared. • Different models of processors cannot be compared so easily. image from http://web.scps.k12.fl.us/site/agenda/default.htm
Instruction Sets ! • A chip’s vocabulary. • Types of instructions that a chip can perform. • Bigger does not necessarily equal better in instruction sets. • CISC: Complex instruction set chips • use complex instructions to process instructions. • RISC: Reduced instruction set chips • break down instructions before processing with a simpler instruction set.
Types of chips: Intel • Intel Pentium 4 – specs • Up to 2.20 GHz • Rapid execution engine • Intel Pentium III - specs • up to 1.33 GHz • 70 new instructions for 3D, voice recognition, etc. • integrated 256 KB L2 cache • Intel Celeron - specs • economy chip • up to 1.30 MHz • integrated 128 KB L2 cache images courtesy of TigerDirect.com, Intel
Types of chips: AMD • AMD Athlon XP - specs • Designed for Windows XP, (works w/ other OS’s) • Up to 1.67 GHz (but runs faster than Pentium 4 2.0 GHz) • integrated 256 KB L2 cache • 266 MHz system bus • AMD Athlon - specs • up to 1.4 GHz • integrated 256 KB L2 cache • 266 MHz system bus • AMD Duron – specs • economical • up to 1.3 GHz • 128 KB L1 cache, 64 KB L2 cache images courtesy of AMD
Types of Chips: Other Brands • Cyrix MII • Motorola PowerPC • Apple • Sun • Digital • others available images courtesy of Sun
ROM? RAM? • Both refer to chip-based memory hardware • (not hard drives, CD-ROMs, etc.) • ROM: Read-Only Memory • doesn’t change (much if at all) • BIOS stored here. • RAM: Random Access Memory • changes frequently • short-term memory
ROM: Read-Only Memory • Chips hardwired with start-up instructions • Non-volatile • not dependent on electrical power to store information • Necessary to start up the operating system (OS) • Has a few options: disk drive boot order, etc.
RAM: Random Access Memory • Synonyms: “main memory”, “primary memory”, “user memory” • Dynamic memory • contents can be changed • Why “random access”? • sequential access vs. random access • analogy: cassette vs. CD • Programs, files stored here while in use. image courtesy of How Computers Work CD
How much RAM do you need? • Current recommendation: 192 MB total RAM for a new computer • Windows 98 uses ~ 20 MB of RAM • Windows 2000 Pro uses ~ 95 MB of RAM • McAfee Virus Scan & Task Manager ~ 7 MB • MS Word uses ~ 7 MB • MS Internet Explorer uses ~ 7 MB • Each file you open is held in RAM, even after you close it
Varieties of RAM: DRAM • DRAM: Dynamic RAM • volatile: needs electricity to hold data. Must be continually replenished with electricity. • SDRAM: Synchronous DRAM • runs at the CPU clock speed (faster than prev. types) • today’s main DRAM.
Variety of RAM: SRAM • SRAM: Static RAM • static: does not need to be continually refreshed. • more expensive, bigger, and faster than DRAM. • used in CPU chips (caches) • used in “flash memory” image courtesy of Sonystyle.com