posted on Apr, 24 2009 @ 09:16 AM
I found the answer at the DELL site. Seems like I was correct in my thinking, but the fan was installed this way on purpose.
"Recently, several online forums and web logs (blogs) have reported that the system fan on the Dell™ Dimension™ 4700 was installed incorrectly
(backwards) from the factory.
While it is true that the fans are installed "backwards" in the system, it is wrong to say this was done incorrectly or by mistake.
The Dimension 4700 system shipped with an aggressive system configuration that required more direct airflow than previously shipped Dimension systems.
For this reason, Dell engineering modified the airflow in the Dimension 4700 to support a cooling solution designed with the fan pulling air into the
chassis. The air is pulled in through the back of the chassis and is directed straight to the CPU heat sink and CPU voltage regulator before finally
passing by the hard drive and out the front of the chassis.
It is correct to say the airflow is backward compared to other Dimension systems. However, without this difference in thermal design, the Dimension
4700 system would not perform nearly as well."