Issue #624 has been reported by Ron Nazarov.

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Bug #624: Memory speed in SMBIOS is incorrectly doubled on Haswell
https://ticket.coreboot.org/issues/624

* Author: Ron Nazarov
* Status: New
* Priority: Normal
* Assignee: Angel Pons
* Target version: none
* Start date: 2026-01-21
* Affected versions: main
* Affected hardware: Haswell
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Tested on a Dell Precision T1700 SFF with NRI, my 1600 MT/s (800 MHz) RAM is 
reported by `dmidecode -t 17` as running at 3200 MT/s.

This bug was introduced in https://review.coreboot.org/c/coreboot/+/89598/6. 
The frequency is doubled in `dimm->ddr_frequency = ddr_freq_mhz * 2; /* In MT/s 
*/`, however (at least on NRI, I did not test MRC), `ddr_freq_mhz` (defined as 
`(mchbar_read32(MC_BIOS_DATA) * 13333 * 2 + 50) / 100`) is actually in MT/s, 
and so already doubled.

I also see this in coreboot logs: `[DEBUG]  memcfg DDR3 clock 1600 MHz`. This 
debug print (added in https://review.coreboot.org/c/coreboot/+/89599/4) is 
printing `DIV_ROUND_CLOSEST(mchbar_read32(MC_BIOS_DATA) * 13333 * 2, 100)`, 
which is pretty much the same as `ddr_freq_mhz` (except using 
`DIV_ROUND_CLOSEST`).



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