Mike Banon has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/30987 )
Change subject: mb/asus: Add Asus A88XM-E FM2+ with documentation ......................................................................
Patch Set 47:
(1 comment)
https://review.coreboot.org/c/coreboot/+/30987/42/src/mainboard/asus/a88xm-e... File src/mainboard/asus/a88xm-e/OemCustomize.c:
https://review.coreboot.org/c/coreboot/+/30987/42/src/mainboard/asus/a88xm-e... PS42, Line 163: /* TODO: is this OK for DDR3 socket FM2? */ : /* : MEMCLK_DIS_MAP(ANY_SOCKET, ANY_CHANNEL, 0x01, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00), : CKE_TRI_MAP(ANY_SOCKET, ANY_CHANNEL, 0x05, 0x0A), : ODT_TRI_MAP(ANY_SOCKET, ANY_CHANNEL, 0x01, 0x02, 0x00, 0x00), : CS_TRI_MAP(ANY_SOCKET, ANY_CHANNEL, 0x01, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00), : */
I would need to inspect AGESA code to understand this. […]
NEW IDEA: although coreboot's AGESA code seems to be not XMP-capable, it could be possible to use a good software like Thaiphoon Burner to copy the available fast "1866MHz CL9" XMP profile in place of some slower JEDEC memory profile. Here are the articles I've discovered: 1) How to apply predefined timing settings from Extreme Memory Profiles on systems with non-compliant XMP BIOS (alter JEDEC timings in accordance with XMP) - https://web.archive.org/web/20180712014302/http://www.softnology.biz/tips_xm... , 2) How to force XMP enhanced memory to operate at 800 MHz on the Apple Macbook Pro 2011. - https://web.archive.org/web/20190720045301/http://www.softnology.biz/tips_ma...
"Today the most exciting memory performance is achieved with DDR3 SDRAM modules and the Intel XMP extension which has now become available on SO-SDIMM parts too. But the XMP extension is an advantage only for DRAM modules being used in systems with XMP compliant BIOS. Unfortunately, the current implementation of UEFI for the Apple MacBook does not provide any over-clocking possibilities and do not support Intel XMP. At first glance, the problem appears to be unsolvable until Apple release an update for UEFI. But if you completely read this article then you have probably already guessed about the idea we are going to share. So, the trick is to copy XMP settings into a regular SPD timing table."
Perhaps I'll need to temporarily flash a proprietary UEFI (which supports XMP memory profiles) before doing this, as a precaution. Also, this approach could work only if SPD memory of these RAM sticks is not write-protected - otherwise it'll be impossible to use software and will require external memory flashing, which I'm not ready to risk.