gnome-shell segfault in libxcb-glx

I'm installing an i386 ubuntu-gnome-16.04-based distro in an old computer (with an amd64 cpu). After logging in at login screen normally, anything the user do (open a shell, firefox, libreoffice, etc) causes gnome-shell to crash.

# dmesg
[ 204.444221] gnome-shell[1947]: segfault at b1dcde80 ip b1dcde82 sp bfe85c9c error 7 in libxcb-glx.so.0.0.0[b1dcb000+18000]
[ 210.826274] gnome-shell[2425]: segfault at b1eb2080 ip b1eb5e82 sp bff94e4c error 7 in libxcb-glx.so.0.0.0[b1eb4000+18000]

Sometimes the segfaults also happen in other libs, like libGL.so, but I couldn't reproduce it when I was collecting this info.

I initially thought it was a hardware issue, but after a bunch of memtests and switches between RAM cards and processors, I'm pretty sure it isn't.

Then I thought it was software. But I've experienced similar problems with clean installations of ubuntu gnome 16.04 (used as base for my distro), including some other kind of errors in the same libs, like "trap invalid opcode" (which I unfortunately couldn't reproduce as well).

Finally, I was certain it was a graphic card issue, because of the situation described above, and also because I was able to workaround this entirely by switching from the on-board card to an off-board card. Although, I've experienced the same problem in another computers with the exact same hardware, and I still can run amd64 systems with the on-board card, which makes me think this card is working as it should.

To make a final addition, the graphics driver seems fine (i915), and I concluded that the problem disappears by downgrading the kernel to 3.3.6 or lower (a 6-year downgrade).

# lspci -k
00:02.0 VGA compatible controller: Intel Corporation 4 Series Chipset Integrated Graphics Controller (rev 03)
 Subsystem: Micro-Star International Co., Ltd. [MSI] 4 Series Chipset Integrated Graphics Controller
 Kernel driver in use: i915
 Kernel modules: i915

I could just use an off-board card or downgrade the kernel, but that would make our work useless, since we need all available graphic cards and a newer kernel to make our multiseat application worth it.