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Intel Core i9 9900K 3.6 GHz (Turbo 5.0GHz) 16 mb cache. Looking at memory specifications it says Max Memory Bandwidth 41.6GB/s. Now choosing the suggested 2666mhz speed for RAM in Dual-channel mode it exceeds this bandwidth limit. What does this mean?

3 Replies
AlHill
Super User
200 Views

Provide the exact model number of your memory sticks.

 

Doc

jgust7
Beginner
200 Views

These are the memory sticks https://www.corsair.com/eu/en/Categories/Products/Memory/Vengeance-PRO-RGB-Black/p/CMW64GX4M4A2666C1....

It's for a school assignment, this is the way i understand it: the memory stick's module name is PC4-21300, 21300 MB/s = 21.3 GB/s x2 dual-channel = 42.6 GB/s?

If that is correct, i would like to now the difference of going over the limit vs going below it. I just find it odd either way.

 

I appreciate the fast response, thankful for any answers.

n_scott_pearson
Super User Retired Employee
200 Views

The BIOS, based upon the SPD (including XMP) settings stored in the DIMMs, is going to program the clocks for the processor's memory controllers and test to ensure that this is a sustainable rate (i.e. noise at this frequency is not overcoming data bit recognition). Now, if this means that data is latched into/out of the DRAM ICs at a rate that is lower than the ICs can sustain, then this additional bandwidth is simply lost. Remember though that this is a burst rate. If the clock rate allows more data to be transferred than can be buffered, then the transfers will be slowed (by injected waits).

...S

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