Disk Drive Controller
The system drive controller is an important part of system performance. In most modern boards your drive controller will run off of the PCI-e bus. The PCI-e bus performance can be affected by poor trace layout as well as many other design choices that show up on different boards.
For testing we use Sisoft's Sandra and Everest.
The P55DE3 is able to keep up with the rest of the P55 pack in terms of HDD (really, SSD) speed.
Stock HDD Performance
Overclocked HDD Performance
Again, HDD speed is where it needs to be.