Ram latency high

[TRraven]

I watched ltt's video on ram timings (luke hosted) and was wondering why my latency is so high. According to his formula my latency should be less than 15ns where as aida 64 is showing me 71ns 

 

ryzen 7 1700 @ 3.8ghz

16gb ddr4 corsair led 13-15-15-33

asrock x370 killer sli/ac

 

anyway why is the latency test in aida so high?

[porina]

70ns sounds about right ball park for an aida64 measurement, depending on actual ram speed and timings. Aida64 does some mix of ram accesses in order to work out the practical latency. If you only look at clock cycles and cycle time, that sounds much lower as it is only looking at one part of the access.

 

Heavily overclocked manually tuned ram might get into 30ms ball park. 

[Mira Yurizaki]

The timings on RAM are internal just to RAM. It does not include delays due to travel time and hops to get to the final destination. In AIDA 64's case:

Quote

Memory latency time means the penalty measured from the issuing of the read command until the data arrives to the integer registers of the CPU.

 

[BobVonBob]

If I had to guess, Aida isn't measuring the same thing that the formula was calculating. Aida is probably seeing how long it takes to pull a full page worth of data from memory, while the formula calculates how long it takes the memory to start accessing that page.

[TRraven]

20 minutes ago, porina said:

70ns sounds about right ball park for an aida64 measurement, depending on actual ram speed and timings. Aida64 does some mix of ram accesses in order to work out the practical latency. If you only look at clock cycles and cycle time, that sounds much lower as it is only looking at one part of the access.

 

Heavily overclocked manually tuned ram might get into 30ms ball park. 

is 70ns generally a good time? I didnt measure what the it was with stock timings

[nick name]

For the 1700 it is where it should be.  That time will reduce with faster RAM and CPU speed also.