[coreboot] RAM speed problem on Supermicro H8QGI (Family 15h)

Константин Аладышев aladyshev at nicevt.ru
Thu Jan 24 08:42:51 CET 2013

I have server Supermicro H8QGI board with 4 AMD Opteron f15 processors and 128 GB RAM (16x8Gb, 4 dimms per socket, 1 dimm per channel).I've tested my board in STREAM and noticed that coreboot gives RAM speed 5 times slower than original BIOS (16 MB/s against 80 MB/s). What can lead to this problem?Is it family 15h or motherboard issue? Does another families have such problem?I've dumped registers from coreboot and original BIOS. After that i enabled/disabled some functions in buildOps.c to make dumps look more similar.Now dumps allmost identical (but RAM speed problem still exist). Also i should mention that original BIOS have HT-ASSIST feature enabled, but i can't enable it in coreboot (http://www.coreboot.org/pipermail/coreboot/2012-December/073001.html)But according to this link http://www.amd.com/us/products/server/processors/six-core-opteron/Pages/six-core-faq-ht-assist.aspx HT-ASSIST can increase performance by up to 60% (not 500%!). So i think it isn't the main problem.
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