1.3 Ray Flashcards
CAS Latency
The delay between when the data is requested and becomes available
Error Correcting Code (ECC)
a type of memory that detects and corrects common errors
When is ECC typically used?
ECC memory is typically only used in servers because it is more expensive than non-ECC.
Which is Faster ECC or Non-ECC
Non-ECC
Consequences of Mixing ECC & Non-ECC
the error correction function would be disabled
Parity RAM
checks for errors but It does not correct them
Non-Parity Ram
This memory does not perform error checking.
Buffered (or registered) RAM
Holds memory addresses or data before it is transferred to the memory controller.
Unbuffered memory
- Does not have a buffer to hold memory addresses or data before transferred to the memory controller.
- Unbuffered memory can be found in servers and high-end workstation.
How are the memory modules in Single-sided RAM organized
Organized into a single logical bank
How are the memory modules in Double-sided RAM organized
Modules are organized into two banks.
Buffered RAM Facts
- Improves stability on systems
- Might slow system performance
Single-Sided vs. Double-Sided RAM Memory Accessibility Comparison
- Single-sided RAM allows access to all of the memory
- Double-sided RAM must switch between banks.
Static RAM (SRAM) power requirements?
Does not require constant power but still requires periodic power to maintain the state of memory,
When is SRAM typically used?
Servers
Dynamic RAM (DRAM) power requirements?
Stores data using transistors which require constant power
If the power is turned off, the data is lost.
Compare SRAM VS DRAM Complexity & Storage Capacity
- SRAM is complex, lower storage capacity
- DRAM simple, high storage capacity
When is DRAM typically used?
Main system memory on a workstation.
DRAM is relatively inexpensive.
How many pins DDR?
Has 184 pins.
DDR2 has how many Pins
240 Pins?
DDR use today?
No longer used in modern motherboards, although you might encounter DDR memory in older systems.
SODIMM Pin Variations? (2)
144 Pin or 200 Pin
How is memory rated?
Rated using Bus Frequency & Bandwidth
(They represent the rate at which data can be read or written)
What does the number following the DDR-, DDR2-, and DDR3
The data transfer rate (Which is the bus frequency *2)
(For example, DDR-400 matches a bus frequency of 200 MHz; DDR2-800 has a bus frequency of 400 MHz; and DDR3-1600 has a bus frequency of 800 MHz.)
Dual-channel systems
Use two memory controllers
Quadruple-channel
Systems use four memory controllers
Does Dual Channel Memory Double Bandwith?
Theoretically it doubles the bandwidth. However, in practice, only a 5–15% increase is gained.
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The delay between when the data is requested and becomes available
CAS Latency
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a type of memory that detects and corrects the common errors
Error Correcting Code (ECC)
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checks for errors but It does not correct them
Parity RAM
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This memory does not perform error checking.
Non-Parity Ram
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Holds memory addresses or data before it is transferred to the memory controller.
Buffered (or registered) RAM
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- Does not hold memory addresses or data before transferred to the memory controller.
- Can be found in servers and high-end workstation.
Unbuffered memory
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Has memory modules that are organized into a single logical bank
Single-sided RAM
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Has modules organized into two banks.
Double-sided RAM
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- Improves stability on systems
- Might slow system performance
Buffered RAM Facts
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Does not require constant power but still requires periodic power to maintain the state of memory,
Static RAM (SRAM)
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Servers typically have what type of RAMs installed?
SRAM
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Stores data using transistors which require constant power
If the power is turned off, the data is lost.
Dynamic RAM (DRAM) power requirements?
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Main memory on a workstation that is also inexpensive?
DRAM
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Has 184 pins.
DDR
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has pins on both sides of the module, with each pin being unique.
DIMM
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Has 144 Pin or 200 Pin
SODIMM
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Theoretically, it doubles the bandwidth. However, in practice, only a 5–15% increase is gained.
Dual Channel Memory
Rated using Bus Frequency & Bandwidth
(They represent the rate at which data can be read or written)
How is memory rated?
