RAM latency and speed question... again?
MinskyBA
Similar questions have been asked many times, I know. I've researched forums all across google and haven't found exactly what I'm looking to know so I'll ask here.
latency vs speed
It's my understanding that the last digit in the timing is essentially the whole number of clock cycles each call takes.
Specifically what I'm looking at is
88826 @ 1800MHz
99928 @ 1866MHz
I'm trying to do the math and figure out which will give better results based on the numbers. Here's how I'm working through it:
Each cycle of 1800MHz takes (1/1800)seconds. 26 clock cycles at this speed results with a time of 26 * (1/1800) = (26/1800) = 0.0144 s
Each cycle of 1866MHz takes (1/1866)seconds. 28 clock cycles at this speed results with a time of 28 * (1/1866) = (28/1866) = 0.0150 s
For my example it would seem that the slower RAM would give the better results. Is this correct?
Also  if the controller is pulling a large chunk of data, does this same lag occur at each bit? just each chunk of data? I know 'burst' comes into play here, but I don't understand exactly how.
If the chip is trying to pull a 10bit chunk from RAM and it incurs this latency at each bit, the latency would seem to be the more important factor. If it only incurs the penalty on the first bit and the subsequent addresses are read with only one cycle latency (which I think is what 'burst' is?) then speed would be more important.
I know the difference here would me extremely minimal, but I'd like to really understand what's going on before choosing.
Any help would be greatly appreciated, even if it's just pointing me to a resource that can guide me.
latency vs speed
It's my understanding that the last digit in the timing is essentially the whole number of clock cycles each call takes.
Specifically what I'm looking at is
88826 @ 1800MHz
99928 @ 1866MHz
I'm trying to do the math and figure out which will give better results based on the numbers. Here's how I'm working through it:
Each cycle of 1800MHz takes (1/1800)seconds. 26 clock cycles at this speed results with a time of 26 * (1/1800) = (26/1800) = 0.0144 s
Each cycle of 1866MHz takes (1/1866)seconds. 28 clock cycles at this speed results with a time of 28 * (1/1866) = (28/1866) = 0.0150 s
For my example it would seem that the slower RAM would give the better results. Is this correct?
Also  if the controller is pulling a large chunk of data, does this same lag occur at each bit? just each chunk of data? I know 'burst' comes into play here, but I don't understand exactly how.
If the chip is trying to pull a 10bit chunk from RAM and it incurs this latency at each bit, the latency would seem to be the more important factor. If it only incurs the penalty on the first bit and the subsequent addresses are read with only one cycle latency (which I think is what 'burst' is?) then speed would be more important.
I know the difference here would me extremely minimal, but I'd like to really understand what's going on before choosing.
Any help would be greatly appreciated, even if it's just pointing me to a resource that can guide me.
1
answer
Last reply
More about latency speed question again

Quote:Each cycle of 1800MHz takes (1/1800)seconds.
Ask a new question
Read More
Memory
Latency
RAM
Related Resources
 CAS latency question!
 RAM Question
 Latency vs. Clock speed
 Lower latency or faster ram speed
 RAM: Latency vs Speed???
 RAM: Latency vs Speed
 Latency or Speed?
 A question of speed and timing.
 RAM > Speed vs Latency vs Voltage
 I7 ram speed vs latency
 Running Same Speed, Different Latency RAM
 2k 9 latency or 1600 7 latency
 CAS latency vs Speed
 What is memmory CAS latency
 Memory Speed or Cas Latency
 Speed vs. latency?
 Question about RAM speed vs. CAS latency...
 DDR3 speed or latency
 Bus speed V Latency question?
 Latency question