OT: Weird Hardware Problem

Arthur Chance freebsd at qeng-ho.org
Tue May 19 13:59:57 UTC 2020

On 19/05/2020 14:46, Tim Daneliuk wrote:
> I was recently given a Dell Inspiron 3847 which has an i7-4790 and 16G
> of memory.  Perfect for multibooting BSD and Linux.  It needed a new power
> supply but now that this is installed, it's exhibiting a very strange
> problem.
> The machine will work for hours flawless and then - for no apparent reason -
> reboot randomly.  The former owner reports that this was also happening
> when they last had it running Win8.
> I've run very heavy loads on it with load averages up to almost 50 - no
> problem.  I've run overnight memory tests which return 0 errors.
> I've run CPU stress tests flawlessly and temperatures were fine.
> One hint here:  I can consistently force the problem to happen if I start
> a Linux installation and request full disk encryption as part of the install.
> I doubt it has anything to with encryption per se, but there is some kind
> of pattern of use that it causing the reboot.
> Has anyone else ever seen something like this and/or have resolution?
> Is there a known bug with that processor?

I've got an i7-4790K (I presume you missed the K) in my desktop and
Intel announced the CPU had problems with the TSX instruction set
extension shortly after I got it, and that those instructions should be
disabled in the BIOS. Other than that I've seen no suggestion anything
else is buggy.

> My first instinct was to blame flakey memory (DDR 1600 2x8G Hynix) but -
> as I said - memory testing is flawless.
> Thoughts and ideas most welcome.

If you hadn't changed the power supply I'd have suggested you look at
that, but otherwise not a clue.

Fat Earther: One who believes the world is round but has put on too
much weight round the middle.

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