In order to get into the system, you don't have to have a screwdriver handy. Simply pull up on the handle which is on the top of the system, and the right side panel flips open, giving you full access to the PC's internals. Dell does an excellent job of keeping things clean internally, as all the components have plenty of access to airflow and there are no rampant cables strewn about. Dell has a nice balance of expandability inside without leaving every possible option open.
A couple major things to note on the insides of the XPS 625, as seen here. The vast majority of the system is cooled by a single 120mm fan which is mounted at the front of the chassis, which includes the CPU itself. The heatsink which is attached to the Phenom II X4 940 processor is a quad-copper heatpipe unit which is completely passive. The airflow must make it from the front of the chassis, through the hard drives, over the CPU, and outside the rear of the chassis, which is a tall order for a low-speed fan.
Not surprisingly, when you put heavy load on the processor, the front 120mm fan has to spin up to high gear in order to get the airflow over on the CPU, which in turn, makes the system extremely loud. During normal desktop operation, the system is pleasantly quiet, as the front fan can spin down to low levels. When gaming or during heavy CPU loading, though, the system is simply unpleasant to be around. If Dell had equipped their CPU cooler with a low-speed fan, this situation could have been avoided entirely, and would have likely allowed them to get rid of the second fan, which is a small fan which sits over the CPU's VRM units, and is also connected to a copper heatpipe-based heatsink.
The cooling issue will only get worse if the system is fully loaded, too. If you have multiple high-speed hard drives and tall, heat producing memory modules, you're putting a lot of high-heat components right in front of your airflow before it even hits the CPU itself. Toss in a pair of hot Radeon 4870 cards in Crossfire mode right above, and you've got an oven right around your passively cooled CPU. Granted, we did not see any instability with our configuration as such, but given the heavy noise levels needed to keep the CPU cool with a fairly minimal configuration, we would say that the maximum system specification would increase the chances of heat related issues to an uncomfortable level. As you can see, the single Radeon 4850 card in our configuration is in a primary PCI Express slot, with a secondary slot for another card via Crossfire. Interestingly enough, the Radeon 4850 only runs at PCI Express x8 mode by default, even with only one card installed. There are also two 32-bit PCI slots, one PCI Express x1 and one PCI Express x8 slot for future additions.
The motherboard has four Serial ATA-II ports pre-wired with cables, two go up to the top of the chassis for optical drives, whereas two go to the bottom for hard disk add-ons. Dell does provide all of the necessary power plugs needed for quick upgrades, but not the necessary cabling for putting in all four hard drives without re-wiring the top of the chassis. The hard disks are also installed in disk caddies for easy sliding in and out, and they also provide some layer of vibration dampening.
The Dell-branded power supply up top supports up to 750W of power, and Dell includes the necessary cabling for multiple graphics cards and to maximize every bit of space in this chassis. All industry standard plugs here, so if you decide to move to a new motherboard, you should be able to without issue (in theory, we didn't try this). In short, it would have been a very nice internal layout, if they would have simply put a fan on the CPU instead of relying solely on the front mounted 120mm cooling fan to keep everything running smoothly.