Ubuntu – Very slow graphics performance after upgrade 12.04 => 14.04

I upgraded from 12.04 to 14.04 and the performance is extremely sluggish; windows open and close in slow motion. Presumably my graphics hardware has not been recognized by the system. I think that I need advice about how to figure out what to do. Maybe I should install some graphics software or maybe I should disable something in Unity, but I don't know where to start.

My 'uname -a' command says this:

Linux home0 3.13.0-24-generic #46-Ubuntu SMP Thu Apr 10 19:08:14 UTC 2014 i686 i686 i686 GNU/Linux

A command 'sudo lshw' gives lots of information and I will try to extract what may be most relevant:

home0
description: Desktop Computer
product: TPS01 ()
vendor: FOXCONN
version: 1.0
serial: To Be Filled By O.E.M.
width: 32 bits
capabilities: smbios-2.6 dmi-2.6 smp-1.4 smp
configuration: boot=normal chassis=desktop cpus=2 uuid=6013CF95-1E02-E531-FD14-D027881B608D

*-core
[...]
*-firmware
description: BIOS
vendor: American Megatrends Inc.
physical id: 0
version: 080015
date: 06/07/2010
size: 64KiB
capacity: 960KiB
capabilities: isa pci pnp apm upgrade shadowing cdboot bootselect socketedrom edd int5printscreen int9keyboard int14serial int17printer int10video acpi usb ls120boot zipboot biosbootspecification

*-cpu:0
description: CPU
product: Intel(R) Atom(TM) CPU D525   @ 1.80GHz
vendor: Intel Corp.
physical id: 4
bus info: cpu@0
version: 6.12.10
serial: 0001-06CA-0000-0000-0000-0000
slot: CPU 1
size: 1800MHz
capacity: 1900MHz
width: 64 bits
clock: 200MHz
capabilities: x86-64 boot fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl tm2 ssse3 cx16 xtpr pdcm movbe lahf_lm dtherm
configuration: cores=2 enabledcores=2 id=3 threads=4
[...]

*-pci
description: Host bridge
product: Atom Processor D4xx/D5xx/N4xx/N5xx DMI Bridge
vendor: Intel Corporation
physical id: 100
bus info: pci@0000:00:00.0
version: 02
width: 32 bits
clock: 33MHz
configuration: driver=agpgart-intel
resources: irq:0

*-display
description: VGA compatible controller
product: Atom Processor D4xx/D5xx/N4xx/N5xx Integrated Graphics Controller
vendor: Intel Corporation
physical id: 2
bus info: pci@0000:00:02.0
version: 02
width: 32 bits
clock: 33MHz
capabilities: msi pm vga_controller bus_master cap_list rom
configuration: driver=i915 latency=0
resources: irq:44 memory:fea80000-feafffff ioport:dc00(size=8) memory:d0000000-dfffffff memory:fe900000-fe9fffff

Addendum: Here is the output from a unity_support_test command.

/usr/lib/nux/unity_support_test -p

OpenGL vendor string:   Intel Open Source Technology Center
OpenGL renderer string: Mesa DRI Intel(R) IGD x86/MMX/SSE2
OpenGL version string:  1.4 Mesa 10.1.0

Not software rendered:    yes
Not blacklisted:          yes
GLX fbconfig:             yes
GLX texture from pixmap:  yes
GL npot or rect textures: yes
GL vertex program:        yes
GL fragment program:      yes
GL vertex buffer object:  yes
GL framebuffer object:    yes
GL version is 1.4+:       yes

Unity 3D supported:       yes

And here is the output from lspci:

lspci -k | grep -A3 VGA

00:02.0 VGA compatible controller: Intel Corporation Atom Processor D4xx/D5xx/N4xx/N5xx Integrated Graphics Controller (rev 02)
    Subsystem: Foxconn International, Inc. Device 0d55
    Kernel driver in use: i915
00:1b.0 Audio device: Intel Corporation NM10/ICH7 Family High Definition Audio Controller (rev 02)

Further addendum: I use this desktop for email, editing, web browsing. I don't care for gaming or for videos and I'll be happy to turn off whatever graphics treatment is associated with this extraordinarily slow behavior. It is not "normal slow" for old hardware; the hardware is i686 from 2010.

Let me clarify "slow". The expected behavior (my experience with 12.04) if I open an Xterm or a browser window is that I see some visual trickery whereby the new window smoothly acquires its size or its color. Under 14.04 the smoothness is all gone; the new window acquires its final state in a jagged manner changing its size or shape maybe once or twice per second over a few seconds. A youtube movie (displayed on Firefox) has a refresh rate of maybe 2 or 3 Hertz. If I type text into the Dash then the characters appear at a rate of maybe 1 per second.

In some similar conversations and questions from back in 2010-2011 I see references to issues with compiz, but I don't know what to do with that information. My System Monitor shows that the CPU usage of compiz shoots up to 48% or so whenever a window is opened; so it is taking essentially all of one CPU on my 2-CPU system. When I drag a window around it is a jagged and lagged motion and compiz usage goes up to 60% or more.

Perhaps it is relevant that my system has another problem as well: libudev.so.0 is not found (as is noticed when Chrome does not start). I really don't know if this may have anything to do with the graphics performance.

By the way, thank you to mikewhatever for editing this post to format the various system outputs as they were meant to be formatted; I had not recognized how to achieve that.