CINEBENCH scores vastly different on nearly identical Mac Pros

hi, I have two Mac Pros (Nehalem 2009). They're practically identical hardware / configs. One of them has more ram and a better graphics card. This better one gets a lower Cinebench score... it makes no sense... i am wondering if there is something faulty with it...

here are the two Cinebench benchmark results, alongside each respective Hardware config...

1st computer - (better graphics card and more ram)

CINEBENCH R10
**************************************************

Tester :

Processor :
MHz :
Number of CPUs : 16
Operating System : OS X 32 BIT 10.5.8

Graphics Card : ATI Radeon HD 4870 OpenGL Engine
Resolution : <fill this out>
Color Depth : <fill this out>

**************************************************

Rendering (Single CPU): 2289 CB-CPU
Rendering (Multiple CPU): 18544 CB-CPU

Multiprocessor Speedup: 8.10

Shading (OpenGL Standard) : 4648 CB-GFX


**************************************************

Model Name: Mac Pro
Model Identifier: MacPro4,1
Processor Name: Quad-Core Intel Xeon
Processor Speed: 2.26 GHz
Number Of Processors: 2
Total Number Of Cores: 8
L2 Cache (per core): 256 KB
L3 Cache (per processor): 8 MB
Memory: 12 GB
Processor Interconnect Speed: 5.86 GT/s
Boot ROM Version: MP41.0081.B03
SMC Version (system): 1.39f5
SMC Version (processor tray): 1.39f5
Serial Number (system): G89 **L20H
Serial Number (processor tray): J591 **F1LUC
<Serial Edited by Host>

2nd computer - worse graphics card, less ram...

CINEBENCH R10
**************************************************

Tester :

Processor :
MHz :
Number of CPUs : 16
Operating System : OS X 32 BIT 10.5.7

Graphics Card : NVIDIA GeForce GT 120 OpenGL Engine
Resolution : <fill this out>
Color Depth : <fill this out>

**************************************************

Rendering (Single CPU): 3132 CB-CPU
Rendering (Multiple CPU): 20344 CB-CPU

Multiprocessor Speedup: 6.50

Shading (OpenGL Standard) : 5034 CB-GFX




Model Name: Mac Pro
Model Identifier: MacPro4,1
Processor Name: Quad-Core Intel Xeon
Processor Speed: 2.26 GHz
Number Of Processors: 2
Total Number Of Cores: 8
L2 Cache (per core): 256 KB
L3 Cache (per processor): 8 MB
Memory: 8 GB
Processor Interconnect Speed: 5.86 GT/s
Boot ROM Version: MP41.0081.B03
SMC Version (system): 1.39f5
SMC Version (processor tray): 1.39f5
Serial Number (system): G89 **20H
Serial Number (processor tray): J591 ***1LUC
<Serial Edited by Host>


it's crazy right? anyone else experience anything like this?

thanks
ben