Solved [Solved] [PC-BSD] Slow boot after adding memory

K

kclark

I've got a very weird problem with my current install. I'm running PC-BSD 9.2 x64 running on ZFS. I have one solid state hard drive for the system and everything else is on my 1TB hard drive (/usr/home, /usr/jails, /var/log, etc). My system was booting just fine using two 4GB sticks of DDR3-1600. I've added one sick of 8GB DDR3-1600 making use of 3/4 memory slots. Once I added the 8GB stick then Grub hangs around for approximately 15 minutes, the screen goes blank, and then GDM is loaded. If I remove the one 8GB stick then everything boots fine. I've ran several memtest's without fail, I've checked my HDD's for the sake of argument, and nothing.

After inspecting the BIOS I've found the mobo is putting itself into single channel, which I would expect since the fourth unused slot doesn't have a matching stick. Does Grub have known problems with larger memory at boot or with single channel mode? It seems like a very weird problem. I did some reading up on this on a Linux man page and the only flag that I can see being helpful at all is mem=. That being said, even the man page seemed iffy about using this since Grub doesn't know which half of the memory the count is starting from. :q

I know this is a PC-BSD system, but I installed FreeBSD because I wanted to reinstall PC-BSD and figured I'd see if FreeBSD (same version) had the same problems since PC-BSD uses FreeBSD as the base system and I was able to recreate it on the build out also.

Here are my conclusions/options:

-Bad memory controller?
-Some undocumented Grub bug with larger memory and/or single channel?
-Grump Cat messing with my system?

Any input would be useful, thanks!
 
Re: Slow boot after adding memory

I did a little reading up on dual channel memory and my mobo. It seems like from the documentation I've found if the dual channel RAM is not installed in pairs then it take a huge performance hit as I expected. There are some threads out there that seem to have problems with Grub 2 and RAM that's been put into single channel. Going to buy another stick tonight and see if this solves my problem.
 
Re: Slow boot after adding memory

Finally got this figured out. After reading through logs I found the following

Code: 
ACPI Warning: Optional field Pm2ControlBlock has zero address or length: 0x0000000000000000/0x1 (20110527/tbfadt-586)

Which I didn't think had anything to do with it, but I did a little bit of googling and found several people with the same type of board as me running various Linux distros. I found that where this warning appeared they also had slow boot times or a total Grub 2 panic. I found one suggestion to update the BIOS. The post I found said this warning doesn't mean anything from the OS side and is a firmware issue.

After updating my BIOS to the most recent version Grub still hangs, the good news is it only hands for at/around 15 seconds. This is not the timeout GRUB is set to. Either way I can live with a 15 second wait instead of a 20 minute boot. I hope this helps someone.
 
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