Chapter 1 Flashcards
How is double-sided memory treated by the system?
As two different memory modules
How many bits of memory are transferred over a standard single memory bank at a time?
64 bits
If a dual-channel memory controller coordinates two memory banks of 64 bits, how many total bits of memory are communicated at a time?
128 bits
If a triple-channel memory controller coordinates three memory banks of 64 bits, how many total bits of memory are communicated at a time?
192 bits
If a quad-channel memory controller coordinates four memory banks of 64 bits, how many total bits of memory are communicated at a time?
256 bits
How do you insert a SIMM (memory module) into a slot?
Insert at a 45 degree angle then maneuver upright to 90 degrees. Then it can be locked in place using clips
How do you insert a DIMM (memory module) into a slot?
Straight into the slot with the locking tabs pulled away from the module. The tabs will automatically snap into place. To remove, simply pull the tabs away to release the module from the slot
When is an ECC algorithm performed?
Whenever the memory is accessed
If there is an error in 3/8 bits of a byte, what will ECC do?
It will not recognise any error
If there is an error in 1/8 bits of a byte, what will ECC do?
It will recognise and correct the error
If there is an error in 2/8 bits of a byte, what will ECC do?
It will recognise but not correct the error
If an ECC algorithm results in all 0s, what will ECC do?
It will pass with no errors recognised
How many bits are present in parity checking in the middle of an algorithm being performed - after transmitting and before receiving?
Nine - an extra bit has been added and will be removed at the receiving end to check the data
How does even parity checking work?
Even parity checking works by storing a 1 in the ninth bit if bits 1-8 are odd; if bits 1-8 are even it will store a 0 in the ninth bit. The 1 triggers an error
How does odd parity checking work?
Odd parity checking works by storing a 0 in the ninth bit if bits 1-8 are even; if bits 1-8 are even it will store a 1 in the ninth bit. The 0 triggers an error
How does parity checking correct an error?
It doesn’t, only shows an error
How does mark parity checking work?
It always stores a 1 in the parity bit; it does not return an error but can be checked
How does space parity checking work
It always stores a 0 in the parity bit; it does not return an error but can be checked
How is parity checking mostly used?
For large scale failures
Where do you find the files for virtual RAM?
At c:\pagefile.sys
When is virtual RAM used?
When lacking primary memory for requests from newly launched applications
Is virtual RAM a good option for regular use?
No, it can slow the whole system. More physical memory should be added if additional primary memory is needed regularly
How is throughput calculated for SDR SDRAM? e.g. 100MHz
8x[rating in name] = 800MBps (throughput is in megabytes per second)
How does SDR SDRAM work?
By transmitting 1 bit of data per data pin for every clock tick
How does DDR SDRAM work?
By doubling pumping the data - instead of 1 bit per pin for every clock tick, it transfers 2 bits total (1 on the rising edge of the clock signal and one on the falling edge)
How does DDR2 SDRAM work
By double pumping the data of a DDR SDRAM
Using an example of an FSB of 200MHz, what would the throughput be of an SDR SDRAM and each of DDR, DDR2, DDR3, DDR4 and DDR5 SDRAM?
SDR SDRAM = 800MBps
DDR SDRAM = 1600MBps
DDR2 SDRAM = 3200MBps
DDR3 SDRAM = 6400MBps
DDR4 SDRAM = 12800MBps
DDR5 SDRAM = 25600MBps
Using an example of an FSB of 400MHz, what would the name be for each of DDR, DDR2, DDR3, DDR4, and DDR5 SDRAM?
DDR SDRAM = PC3200
DDR2 SDRAM = PC2-6400
DDR3 SDRAM = PC3-12800
DDR4 SDRAM = PC4-25600
DDR5 SDRAM - PC5-51200
Why isn’t DDR SDRAM hotter than SDR SDRAM?
Because increased heat is caused by increasing clock frequency, and DDR doesn’t increase the clock frequency, just the amount of data transmitted over that frequency
Is industry standard for the clock rate used for speed of FSB based off DDR or SDR SDRAM?
DDR SDRAM
What is the calculation for SDRAM module throughput?
(FSB in Mhz) x 8MB = throughput in MB
Where would you use a SODIMM memory slot?
For smaller devices such as laptops and mobiles
Where would you use a DIMM memory slot?
For larger devices such as PCs
What are DIMMs?
DIMMs are 64-bit memory modules that package SDRAMs
Why aren’t DDRs forwards or backwards compatible?
The keys are in different places
Are SODIMMs interchangeable?
No
Is DDR5 available in SODIMM?
Yes
How are pins distributed on a DIMM?
Half on either side
How many pins does a DDR DIMM have?
184
How many pins does a DDR2 DIMM have?
240
How many pins does a DDR3 DIMM have?
240
How many pins does a DDR4 DIMM have?
288
How many pins does a DDR5 DIMM have?
288
How many pins are there on each of a DDR, DDR2, DDR3, DDR4 and DDR5 DIMM?
184, 240, 240, 288, 288
How many channels are on DDR SDRAMs of any type?
1
What is the maximum memory available on a DDR SDRAM?
1GB
What is the maximum memory available on a DDR2 SDRAM?
8GB
What is the maximum memory available on a DDR3 SDRAM?
32GB
What is the maximum memory available on a DDR4 SDRAM?
64GB
What is the maximum memory available on a DDR5 SDRAM?
128GB
What is the maximum memory available on each of a DDR, DDR2, DDR3, DDR4 and DDR5 SDRAM?
1GB, 8GB, 32GB, 64GB, 128GB
What is the peak voltage of a DDR SDRAM?
2.5V
What is the peak voltage of a DDR2 SDRAM?
1.8V
What is the peak voltage of a DDR3 SDRAM?
1.5V
What is the peak voltage of a DDR4 SDRAM?
1.2V
What is the peak voltage of a DDR5 SDRAM?
1.1V
What are the common data rates of a DDR3 SDRAM?
800Mbps-2133Mbps
What are the common data rates of a DDR4 SDRAM?
1600Mbps-2133Mbps
What are the common data rates of a DDR5 SDRAM?
64Gbps
If both DDR3 and DDR4 SDRAMs only go up to 2133Mbps in terms of data rates, why would a DDR4 still be preferable?
Because the beginning data rates are still higher, so a lower cost DDR4 with lower data rates will still be higher than the lowest cost DDR3 with lowest data rates
Which memory module has on-die ECC?
DDR5 SDRAM
Scenario: what memory module (and associated memory packaging) would you use for a laptop requiring a lot of memory?
DDR5 SODIMM
