There's really no major changes in the outward appearance of the 'P' chassis that Shuttle uses with both the SB95P we reviewed earlier, and the SD31P. The front panels are a shade darker, perhaps now more like true gunmetal than the lighter grey we saw before. It's a subtle touch, and it definitely looks better in its current incarnation. The outer shell retains the same black finished aluminum, with vents placed along the right and left sides, in line with the CPU and ICE cooling system.
The SD31P has two external drive bays, one each for 3.5" and 5.25" size drives, and a front I/O panel concealed along the bottom behind a retractable face plate. The I/O panel has two audio jacks as well as two USB ports and a FireWire port for easier connectivity. Additionally, there's a slim-line 8-in-1 card reader at the top, capable of reading all popular formats. The rear of the chassis is a mixture of fan grills and ports. Reflecting on the fact that there isn't as much room as one would find in a full-sized tower, it's amazing that the rear doesn't appear to be as cluttered as it could be. Two slots are placed along the left side for the PCI-e graphics and another add-in card. The center of the unit is dominated by two upper zone fans and a larger fan that comes as part of the 350W PSU. Down below are the full assortment of ports, including a 15-pin VGA port to support the on-board graphics, 4 USB 2.0 ports (up from 2 ports on the SB95P) and a SATA hot-plug. Not to be undone, off to the right of the fans is an additional FireWire connection, which they couldn't fit on the I/O plate. We also completely missed the 'Clear CMOS' button upon our original inspection; placed, yet unlabeled in the upper left corner. Shuttle assures us this will be clearly marked on production models.
The Integrated Cooling Engine (ICE) module appears to be the same unit that we had taken a look at earlier. The ICE module uses convection cooling to transfer heat quickly away from the CPU. Four tall copper heatpipes are plated in nickel, and are surrounded by radiator fins. There are two fans on either side of the heatsink, with one side pulling in cooler air from outside the chassis and a larger, quieter 92mm fan exhausting the air out the other side. The fans can be controlled via the BIOS allowing for various speeds depending on the user's performance/noise desires. Power for the SD31P is supplied by a 350W SilentX PSU, providing 100W more than the typical small form factor PSU. One new addition that's sure to be appreciated by power users is the inclusion of a PCI-Express power connector coming off of the PSU.
In our last foray in the building of the Shuttle SB95P, we had a few problems with their toolless drive installation that we hoped would be corrected. We commented on three issues: what seemed to be weak retention brackets, a 4-pin hard drive locking mechanism and some "radiation" shields that did nothing more than come loose and bang around the inside of the chassis. Well, we can say for certain that Shuttle may be one of the few manufacturers that definitely takes analyst's and owner's comments to heart, as all three of these issues have been resolved. When the cover was removed from the SD31P. we saw that the drive tray was held down tightly by the SATA hard drive clips. These rails have small indents that rest within the frame as before, but the ends fit into specifically placed slots and then clips are locked down assuring a tight connection.
Once the clips are removed, the tray can be removed in order to install the floppy drive or IDE hard drive, and an optical drive. The four pin/retention scheme has been removed entirely. Rather than simply resting the hard drive onto the pins, side rails are clipped onto the drive, which are then slid into the channels on the frame and locked into place. The same basic procedure is followed for an optional floppy drive and the CD or DVD-ROM. It takes a little force to get the drives to slide back all of the way, but once there they were solidly locked in. Also completely gone were the shields we disapproved of in our SB95P review.