Associate
- Joined
- 5 Jun 2005
- Posts
- 987
- Location
- Leicestershire
You would be surprised. (I have seen similar behaviour yes.) I would say yes you should try to use washers, particularly as the system works fine outside the box. Virtually all motherboards supply little red washers to use under the screws that go into the standoffs the motherboard rests on, they probably do that with intent.
Although in most cases you will find that they're not really neccessary, in some cases they actually are and in yours I would say you should just do it and see if the problem goes away. (In some cases I've even put washers under the motherboard (on top of the standoffs) in some builds although that strictly speaking also shouldn't be neccesary. Also, that's terribly fiddly to get right - trying to place the motherboard on the standoffs without knocking any of the washers off is rather challenging.) Nevertheless, your tests suggest washers may help, so that's the logical next step... 
or dry joint or something that's not causing problems when the board is outside the box but that might just be causing enough of a duff connection when in the box (and thus under some slightly increased strain possibly) to cause the instability you're seeing. 
