I'm trying to test this out now. Keep in mind this may not be a kernel issue and could be something else wrong with the stack.

Here are some interesting stuff from dmesg:

[10543.371193] [drm:intel_pipe_config_compare] *ERROR* mismatch in adjusted_mode.flags (expected 1, found 0)
[10543.371203] ------------[ cut here ]------------
[10543.371270] WARNING: CPU: 2 PID: 1734 at /build/buildd/linux-3.11.0/drivers/gpu/drm/i915/intel_display.c:8292 check_crtc_state+0x58f/0x9c0 [i915]()
[10543.371274] pipe state doesn't match!
[10543.371277] Modules linked in: ipt_MASQUERADE(F) iptable_nat(F) nf_nat_ipv4(F) xt_CHECKSUM(F) iptable_mangle(F) bridge(F) stp(F) llc(F) bbswitch(OF) pci_stub vboxpci(OF) vboxnetadp(OF) vboxnetflt(OF) vboxdrv(OF) ebtable_nat(F) ebtables(F) hid_generic hidp x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel(F) kvm(F) ip6t_REJECT(F) xt_hl(F) joydev(F) ip6t_rt(F) parport_pc(F) ppdev(F) nf_conntrack_ipv6(F) nf_defrag_ipv6(F) rfcomm ipt_REJECT(F) xt_LOG(F) bnep xt_limit(F) xt_tcpudp(F) xt_addrtype(F) nf_conntrack_ipv4(F) nf_defrag_ipv4(F) uvcvideo xt_conntrack(F) videobuf2_vmalloc videobuf2_memops videobuf2_core videodev wacom ip6table_filter(F) ip6_tables(F) nf_conntrack_netbios_ns(F) nf_conntrack_broadcast(F) arc4(F) nf_nat_ftp(F) nf_nat(F) btusb nf_conntrack_ftp(F) snd_hda_codec_conexant bluetooth nf_conntrack(F) iwldvm iptable_filter(F) ip_tables(F) mac80211 snd_hda_intel snd_hda_codec x_tables(F) snd_hwdep(F) snd_pcm(F) thinkpad_acpi snd_page_alloc(F) nvram(F) iwlwifi snd_seq_midi(F) snd_seq_midi_event(F) microcode(F) snd_rawmidi(F) cfg80211 psmouse(F) snd_seq(F) serio_raw(F) snd_seq_device(F) snd_timer(F) snd(F) wmi mei_me mei lpc_ich tpm_tis soundcore(F) nfsd(F) mac_hid auth_rpcgss(F) nfs_acl(F) nfs(F) lockd(F) binfmt_misc(F) sunrpc(F) fscache(F) ext2(F) lp(F) parport(F) xts(F) gf128mul(F) dm_crypt(F) usbhid hid crct10dif_pclmul(F) crc32_pclmul(F) i915 ghash_clmulni_intel(F) cryptd(F) i2c_algo_bit drm_kms_helper sdhci_pci drm sdhci ahci(F) libahci(F) e1000e(F) ptp(F) pps_core(F) video(F) [last unloaded: nvidia]
[10543.371428] CPU: 2 PID: 1734 Comm: Xorg Tainted: PF          O 3.11.0-11-generic #17-Ubuntu
[10543.371432] Hardware name: LENOVO 4180J4C/4180J4C, BIOS 83ET57WW (1.27 ) 05/17/2011
[10543.371437]  0000000000000009 ffff8801b0e57898 ffffffff816f2b39 ffff8801b0e578e0
[10543.371444]  ffff8801b0e578d0 ffffffff81061dbd ffff8801afa126d0 0000000000000001
[10543.371450]  ffff8801b02ed800 ffff8801afa12000 ffff8801b02edc78 ffff8801b0e57930
[10543.371456] Call Trace:
[10543.371469]  [<ffffffff816f2b39>] dump_stack+0x45/0x56
[10543.371481]  [<ffffffff81061dbd>] warn_slowpath_common+0x7d/0xa0
[10543.371488]  [<ffffffff81061e2c>] warn_slowpath_fmt+0x4c/0x50
[10543.371528]  [<ffffffffa01369ef>] check_crtc_state+0x58f/0x9c0 [i915]
[10543.371566]  [<ffffffffa0141bf3>] intel_modeset_check_state+0x2c3/0x770 [i915]
[10543.371598]  [<ffffffffa0142135>] intel_set_mode+0x25/0x30 [i915]
[10543.371629]  [<ffffffffa0142982>] intel_crtc_set_config+0x742/0x910 [i915]
[10543.371664]  [<ffffffffa009af8d>] drm_mode_set_config_internal+0x5d/0xe0 [drm]
[10543.371695]  [<ffffffffa009d9c7>] drm_mode_setcrtc+0xf7/0x650 [drm]
[10543.371728]  [<ffffffffa0137f72>] ? intel_crtc_load_lut+0xd2/0x170 [i915]
[10543.371754]  [<ffffffffa008e212>] drm_ioctl+0x532/0x660 [drm]
[10543.371774]  [<ffffffff811b8ba5>] do_vfs_ioctl+0x2e5/0x4d0
[10543.371783]  [<ffffffff811a91f1>] ? __sb_end_write+0x31/0x60
[10543.371791]  [<ffffffff811a6d82>] ? vfs_write+0x172/0x1e0
[10543.371799]  [<ffffffff811b8e11>] SyS_ioctl+0x81/0xa0
[10543.371808]  [<ffffffff817029dd>] system_call_fastpath+0x1a/0x1f
[10543.371813] ---[ end trace b32bbac660314e53 ]---

[11461.459165] [drm:i915_hangcheck_elapsed] *ERROR* stuck on render ring
[11461.459173] [drm] capturing error event; look for more information in /sys/kernel/debug/dri/0/i915_error_state
[11461.472321] [drm:i915_set_reset_status] *ERROR* render ring hung inside bo (0xb7a5000 ctx 1) at 0xb7a51c8
[11468.428420] [drm:i915_hangcheck_elapsed] *ERROR* stuck on render ring
[11468.428488] [drm:i915_set_reset_status] *ERROR* render ring hung inside bo (0x344b7000 ctx 1) at 0x344b71c8


I'm also affected by this bug: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1041790 and the work around does not work for me. This only happens when I'm playing games (entire screen locks up)

I use 2 monitors, too.