Most of the graphics tests I've tried (eg nexuiz) won't run.

The benchmark kicks off, I get a splash screen (distributed across 2 monitors in a multi-monitor setup) and then "The test run ended prematurely"

This is almost certainly related to the multiple monitor setup. There needs to be an option somewhere to tell the benchmark to run on a specific screen rather than trying to span multiple monitors.

Code:
$ phoronix-test-suite detailed-system-info

Phoronix Test Suite v4.6.1
System Information

Hardware:
Processor: AMD Phenom II X4 940 @ 3.00GHz (4 Cores), Motherboard: Gigabyte GA-MA780G-UD3H, Chipset: AMD RS780 + SB7x0/SB8x0/SB9x0, Memory: 8192MB, Disk: 2 x 1000GB Western Digital WD1001FALS-0 + 3001GB Seagate ST3000DM001-9YN1 + 3001GB Seagate ST3000DM001-1CH1, Graphics: AMD Radeon HD 7800 2048MB (1000/1200MHz), Audio: Realtek ALC889A, Monitor: P244W, Network: Realtek RTL8111/8168B

Software:
OS: Ubuntu 12.04, Kernel: 3.2.0-48-generic-pae (i686), Desktop: GNOME 3.2.1, Display Server: X Server 1.11.3, Display Driver: fglrx 13.10.10, OpenGL: 4.2.12337, Compiler: GCC 4.6, File-System: ext4, Screen Resolution: 1920x1080


PROCESSOR:

Core Count: 4
Thread Count: 4
Cache Size: 512 KB
Instruction Set Extensions: SSE 4a
AES Encryption: NO
Energy Performance Bias: NO
Virtualization: AMD-V
Compiler Configuration: --build=i686-linux-gnu --disable-werror --enable-checking=release --enable-clocale=gnu --enable-gnu-unique-object --enable-languages=c,c++,fortran,objc,obj-c++ --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-nls --enable-objc-gc --enable-plugin --enable-shared --enable-targets=all --enable-threads=posix --host=i686-linux-gnu --target=i686-linux-gnu --with-arch-32=i686 --with-tune=generic -v
Disk Mount Options: barrier=1,data=ordered,relatime,rw,user_xattr
Cpu Scaling Governor: powernow-k8 ondemand
How do I make this work?