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
What is Serial Presence Detect
The motherboard will automatically detect the new RAM installed.
The PC queries the SPD chip to notify the MCC how much is available
What are Real Parity Errors
The same error will happen in the same place with a Unique address
What are phantom parity errors
Will show up on systems that don’t have parity or ECC memory.
Will show different addresses.
Sign of software issues, heat or dust
What are Page faults
Mild error code that could be caused by the memory
What is a Non Maskable Interrupt
An interruption that the CPU cannot ignore resulting in BSOD
What are four characteristics of Statis Random Access Memory
- Faster than DRAM
- More Expensive
- Volatile
- Utilized for CPU
What are 4 characteristics of Dynamic Random Access Memory
- Volatile
- Slower than SRAM
- Widely used for systems primary storage
- Less expensive
In computer architecture, what does the term “word” refer too
A group of bits processed as a unit.
What is the number of pins on SDR SDRAM?
168
How are the speeds of DDR3 calculated
PC speed rating = CLK * 8
Bandwidth = CLK * 8
What are 4 characteristics of DIMMS
- Printed circuit board used as a placeholder for memory chips
- Separate electrical contacts on each side
- 64 bit data path
- Used with SDRAM types
What is the number of pins used by SO-DIMM DDR SDRAM modules
200
DDR2 SO-DIMM used _ pins?
144
SO-DIMM DDR3 uses how many pins?
204
MicroDIMM DDR uses how many pins
172
MicroDIMM DDR2 uses how many pins
214
What is buffered memory
have a register between the DRAM modules and the system’s memory controller.
What RAM types are used for servers
RDIMM
ECC memory
Buffered Memory
