Unit 6: Lets discuss the different kinds of Memory! Rajeev Gupta (Mr. RAJ)

1. Unit 6: Lets discuss the different kinds of Memory! Rajeev Gupta (Mr. RAJ) 15 Years of IT & Training Experience in Hardware and Networking. Training is my Passion. I am really excited about brining this information to you. I will do my best to give you a perfect place to launch an IT career and I promise it will help you tremendously in knowing how the PC works. You will be building on the foundation no matter where you go.

2. Measuring memory • Cells • Store a single bit of data • 0 or 1 • Represents on/off or yes/no • Measurement units • Bit • Nibble = 4 bits • Byte = 8 bits • Word = based on CPU • 32-bit processor: 32-bit word • 64-bit processor: 64-bit word • Byte (B) = 8 bits • Kilobyte (KB) = 1024 bytes • Megabyte (MB) = 1024 KB = 1,048,576 bytes • Gigabyte (GB) = 1024 MB = 1,073,741,824 bytes • Terabyte (TB) = 1024 GB = 1,099,511,627,776 bytes

3. Memory types • Classify memory as: • Volatile vs. non-volatile • Static vs. dynamic • Asynchronous vs. synchronous

4. Dynamic vs. static memory • Dynamic (DRAM) • Must be continually refreshed • Inexpensive • Small • Static (SRAM) • Refreshing not required • More expensive • Larger • Faster • Typical uses • Main system memory: DRAM • Cache memory and CMOS: SRAM

5. Asynchronous vs. synchronous • Asynchronous • Not synchronized to system clock • Consistent time to access and read data • Synchronous • Synchronized to system clock • Accesses data and returns in one or more clock cycles • SDRAM faster than ADRAM

6. Why RAM is needed Processor RAM Hard Disk Registers Data and instructions Kernel of O.S. O.S. Currentlyrunning Programs User Files ALU Currently open files Programs Control Unit External Data Bus

7. Pentium CPU The data bus and the address bus are collectively know as the frontside bus The Northbridge chip connects all intelligent peripherals e.g. CPU, RAM, graphics North Bridge (Memory Controller) Dimm 1 (168 pin) 64 bits wide

8. Development of RAM 80286 = 16 bit external data bus 386/486 = 32 bit external data bus Pentium = 64 bit external data bus or The DIMM was developed to keep pace with the 64 bit external data bus of the Pentium processor or Intel and AMD are currently planning processors with 128-bit external data buses. These systems will need 2 64-bit 184-pin DIMMs per bank

9. Banking RAM Motherboard manufacturers organize RAM slots electronically into banks. Each “bank” of data can deliver the full width of the external data bus. A bank on a 486 is 32 bits wide. A bank on a Pentium is 64 bits wide No. of SIMMs/DIMMs in a bank Width of external data bus  bit width of the SIMM or DIMM = Questions Q1. How many 72-pin SIMMs are needed to fill a bank on a Pentium Pro? Q2. How many 184-pin DIMMs are needed to fill a bank on an Athlon XP?

10. Development of RAM • 8088 – 1Mb of RAM • 286 – 4Mb of RAM • 486 - 16Mb of RAM • Pentium - 32Mb of RAM • Pentium II - 64Mb of RAM • Pentium IV or Athlon – 128Mb to 4Gb RAM • Athlon 64 – potentially 172,000,000 Gb RAM!!!

11. Measuring RAM • Made up of individual bits which are 1’s or 0’s (5v or 0v) • 8 bits = 1 byte • A byte represents a character, number or symbol • 1024 bytes = a kilobyte • 1024 kilobytes = a megabyte • 1024 megabytes = a gigabyte

12. Volatile: Loses contents without power • Non-volatile: Keeps contents without power

13. RAM – Basic Points • Temporary storage area for programs and data • Volatile • Very fast – in some cases thousands of times faster than a HDD • Accessing data from RAM • RAM is very sensitive to ESD – always store in anti-static bags!

14. Memory access types continued

15. Memory access types, continued

16. Access time • Latency • Memory speed • Nanoseconds vs. megahertz • Overall speed • Doesn’t include latency • Doesn’t consider bus speed • Bandwidth

17. Speed ratings

18. Packaging • Early PCs used individual chips • No more than 1 MB of memory continued

19. Packaging, continued • Package • Small circuit board • Also called a module • Installed in slot • Module contains • Memory chips • Connecting wires • Support chips • Pins or edge contacts

20. Single- and double-sided modules • Early DRAM had chips on just one side • Double memory by placing chips on both sides • Double-sided modules have two rows of pins at bottom • Pins on front aren’t connected to pins on back • Number of DRAM chips no longer corresponds to data being stored

21. DIPP • Dual Inline Pin Package • Connected directly to the motherboard • Took up a lot of space on the motherboard • Replaced by SIPPs

22. DIPPs soldered into a motherboard

23. SIPP • Single Inline Pin Package • Eliminated need for individually installing memory modules • 30 pins but easy to break • Very quickly replaced by 30-pin SIMMs

24. RAM SIMM • Single In-Line Memory Module • FPM (Fast Page Mode) DRAM • 30 or 72 pin connector • 30-pin SIMM could send/receive 8 bits of data • Parity checking • Installed in pairs due to 16 bit memory bus of the 80286 processors • 72-pin SIMM could send/receive 32 bits of data • 80386 and 80486 processors had a 32 bit memory bus and used 72 pin SIMMs allowing up to 256Mb RAM • A SIMM can be single or double sided

25. Calculating 72-pin SIMM capacity 4 x 32 SIMM module Each 72-pin SIMM is 32 bits wide has 4 x 32 megabit chips on the circuit board

26. 72-pin SIMM Questions Write down the capacities of the 72-pin SIMM modules corresponding to the specifications listed below 1 x 32 4 x 32 8 x 32 16 x 32

27. RAM DIMM • Dual In Line Memory Module • All DIMMs are 64 bit • 168-pin used for DRAM and SDRAM • 184-pin used for DDR RAM • Send/receive 64 bits of data • Capacity of 8Mb to 1Gb per module • ECC • A DIMM can be single or double sided

28. RAM SODIMM • Small Outline Dual In Line Memory Module • 144 pin • Used in laptops • Physically smaller than standard DIMMs

29. RAM RIMM • Rambus inline memory module (aka RDRAM) • Used only in Pentium 4 systems • Uses heat spreader • 184-pin RIMM for desktops • 160-pin SORIMM for laptops • RIMMs must be installed in pairs • Continuity RIMMs (CRIMMs) installed in unused slots

30. DRAM Types • FPM RAM • EDO RAM • SDRAM • DDR SDRAM • RDRAM • VRAM • WRAM

31. FPM RAM • Fast Page Mode Random Access Memory • Access speed = time taken for FPM chip to supply Northbridge with data – measured in nanoseconds • 60ns is faster than 100ns

32. EDO RAM • Extended Data Out Random Access Memory • Early 1990’s – used with some 486’s and with Pentiums • Came in 72-pin SIMM or 168-pin DIMM • Needed special Northbridge design • Needed less refreshing than FPM RAM so data was available to the processor more often • Maximum transfer rate to L2 cache is 264 MBps. • Used throughout the 1990’s • Eventually replaced by SDRAM

33. SDRAM • Synchronous Dynamic Random Access Memory • Tecnically correct name is SDR SDRAM • 4 to 6 times faster than FPM and EDO RAM • Linked to the system clock on motherboard (Unlike FPM and EDO) – resulting in less time wasted by the processor waiting for data • (66, 75, 83, 100, 133) Mhz are the common SDRAM speeds • N.B. SDRAM speed must be equal to or faster than the motherboard speed • 168-pin DIMMs • PC100/133 standards • Maximum transfer rate to L2 cache is 528 MBps

34. Double Pumping • First used with AMD Athlon processor • Enabled the Athlon to send/receive two bits of data with every clock cycle to/from the Northbridge • Effectively doubles the system bus speed (motherboard speed) • Athlons with 100 Mhz or 133Mhz FSBs between the Northbridge and the CPU ran at 200Mhz or 266Mhz • Double Pumping systems use DDR SDRAM System clock speed (motherboard speed) 266Mhz 133Mhz CPU Northbridge DDR SDRAM

35. Quad Pumping Pentium 4’s with 100 Mhz or 133Mhz FSBs between the Northbridge and the CPU ran at 400Mhz or 533Mhz • SDRAM wasn’t fast enough to handle the quad-pumped Front-side Bus • Intel developed their own Rambus DRAM instead (RDRAM) • Quad Pumping systems use RDRAM (effectively Pentium 4’s) System clock speed (motherboard speed) 533Mhz 133Mhz CPU Northbridge RDRAM

36. DDR SDRAM • Double Data Rate synchronous dynamic RAM • Processor can read/write from DDR SDRAM on both the up and down cycle of the clock • Works with Athlon and later AMD processors double-pumped FSB • Runs at 200, 266, 333 or 400 MHz • 184-pin DIMMs • Maximum transfer rate to L2 cache is 1064 MBps • Intel has given in and now supports DDR SDRAM!

37. Naming DDR SDRAM Speed in Mhz of DDR RAM module X Pentium IV and AMD processors have a 64 bit data bus which is 8 bytes 8 bytes then Round up or down to the nearest 100 Eg: 200 Mhz DDR SDRAM = PC1600

38. DDR SDRAM Questions Write down the DDR SDRAM module names corresponding to the speeds listed below. 200 Mhz (DDR200) 266 Mhz (DDR266) 333 Mhz (DDR333) 400 Mhz (DDR400) It’s possible to mix DDR SDRAM speeds on the same motherboard. Check the manual for accepted speeds before you attempt this!

39. Package types: laptops • MICRODIMM 144-pin • SODIMM 144-pin • SODIMM 200-pin • DDR • DDR2 • SODIMM 204-pin

40. Memory error recovery • Parity — Detects an error • ECC — Detects and corrects an error • Desktop memory — No parity or ECC • Server memory — Often includes parity or ECC

41. Parity 8 chips, no parity 9 chips, supportsparity

42. Memory installation considerations • Banking requirements • Proper handling techniques • Slot insertion techniques • Safe storage • BIOS configuration

43. Banking requirements • Install memory in groups called banks • Bank might include 1, 2, or 4 slots • Must fill every slot in a bank • Might have to use same type and speed of memory in every slot • Leave extra banks empty • With DRDRAM, install continuity modules • Dual-channel architecture • Specific to motherboard

44. Proper handling • Unplug computer before opening it • Ground yourself to computer’s chassis • Move around as little as possible • Lay module in static-safe packaging atop the computer’s power supply to safely discharge potential differences • Always handle modules by their edges • Never touch chips or contacts

45. Inserting memory modules • Insert module at 45-degree angle • While pushing into slot, move module to fully vertical or horizontal position • Clips should engage automatically when module is fully seated

46. Removing a module • Gently release the retaining clips at both ends of the module • Move the module to a 45-degree angle • Remove the module

47. Storage • Store in: • Original packaging • Static-safe bag • Static-safe bag • Metal-coated plastic • Conductive • Transmits static charges slowly

48. CMOS configuration • BIOS checks memory at boot • Compares actual memory with CMOS entry • Follow prompt to update CMOS entry

49. Memory in handheld computers • Expandable memory, a feature of more expensive handhelds • Some use modules similar to those in notebooks • Others use memory cards similar to those in digital cameras • Consult the manual

50. Task Manager • Windows GUI utility • Provides information on processes running • Version available in all Windows OSs • Windows 9x/Me Program List • Windows NT/2000/XP/Vista Task Manager • Access: • Ctrl + Alt + Delete • Right-click empty space in the taskbar and choose Task Manager • Ctrl + Shift + Esc