ch5_RAM Flashcards
How does DRAM organize data in memory
Like a spreadsheet with numbered rows and columns containing 1 or 0
RAM is made up of what?
Microscopic Capacitors and transistors
How wide can rows be (Currently)
64 bits, 32 bits
Who organizes the data into 8 bit chunks
MCC
What types of RAM are there
SDRAM = Synchronous DRAM RDRAM = Rambus DRAM DDR SDRAM (2, 3, 4)
What are the specs for SDRAM
Tied to the system clock which results in wasted time
Dual Inline Memory Modules, SODIMM in Laptops (Small Outline)
168 pins
Clock Speeds
66, 75, 83, 100, 133
What is RDRAM
Handles Speeds up to 800 MHz
They were costly and similar to SDRAM
What are the key differences in DDR SDRAM
- Double Data Rate SDRAM = 2 bits
- 184 pins
- SO DIMM = 200 pins
- MicroDIMM = 172
- PC rating - PC3200 = 200 MHz (/8) - [CLK]*8
What are the key differences in DDR2
- Reads/Writes 4 words of data per clock cycle
- 240 pins
- PC speed rating = CLK * 8
DDR2-1066 = PC2-8500 - Bandwidth = CLK * 8
What are the key differences in DDR3
- Reads/Writes 8 words of data per clock cycle
- Clock signal quadrupled = two transfers per cycle
- 240 pin
- 16 GB max
What are the ratings for DDR3?
Core RAM Speed (cRAM) [MHz]
DDR I/O Speed (DRIO)
DDR3 Speed Rating = [DDR3-]
PC Speed Rating = [PC3-]
What are the key differences DDR4
Higher Density, lower voltage Handles high speeds better voltage between 1.2 V and 1.4 V 16 banks versus 8 in DDR3 64 GB max 288 pin
What are the ratings for DDR4 and how are they calculated?
Clock Speed = CLK [MHz] = 266 MHz
Bandwidth = CLK * 8 [MT/s] = 1600 MT/s
DDR4 Speed = [DDR4-] CLK * 8 = DDR4=2133
PC Speed Rating = [PC4-] * 64 = PC4-17000
What is Latency
Delay when receiving the next address.
CL6 = Low latency
What is CL
Clock Cycle Delays
DL6 = 6 cycle delays before delivering
What is CAS
Column Array Strobe
Helps the MCC find the particular bit of memory it needs. Needs charge to do its job
What is Parity
Stored an extra bit of data to verify whether the data was correct and can repair
What is ECC
Error Correction Code
Detects any time a single bit is incorrect. Slower than normal RAM. Motherboard needs to support ECC
What is the purpose of a register on the module
To act as a buffer between DIMM and MCC to compensate for electrical problems
What is Virtual Memory
A portion of the HDD is used as an extension of the System RAM
Recommended Size is 1.5 RAM installed
How does this portion of virtual memory show in the HDD
Page file or Swap File
What is the purpose of a page file
Programs are moved to page file when not in use to make room for active applications, but it is not as fast as RAM
What is Disk Thrashing
Windows frequently moving programs between RAM and page file - This is a sign that More RAM is needed
What is ready boost
Enables a USB drive to be used as a super fast dedicated virtual memory
4 GB is ideal
