What timings would CL16 3200 mhz RAM run on a B460 board?

3dprophet

n00b
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Oct 9, 2020
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If I used CL16 3200 mhz ram on a B460 mobo, what timings would the board select if I wanted to run at 2666 mhz?

For example if the ram has XMP of 16-18-18-36 at 3200 mhz, and SPD of 15-15-15-36 at 2133 mhz. How does the motherboard select the timing at 2666 mhz?
 

E4g1e

Supreme [H]ardness
Joined
May 21, 2002
Messages
7,252
Problem is this:

At XMP, if the board selects 2666 speed, it will use the exact same timings as it does at 3200 speed - in this case, the same 16-18-18-36 timings. This is because the DIMMs have absolutely no profiles at 2666 speed, and the XMP profile overrides the autodetected JEDEC selection with the manual profile settings.

If on the other hand you don't select XMP, and you manually select 2666 speed, the B460 board will use timings of 19-19-19-46 for that particular memory kit. (By the way, 19-19-19 is one of the official JEDEC timing specs for DDR4-2666 RAM - in fact, CL19 is around the middle of the JEDEC-standard CAS latency range for DDR4-2666 RAM.)

To manually translate the XMP settings to 2666 speed, you will need to manually set timings of 14-15-15-30.
 
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