Taking the system apart for minor upgrades is rather easy; however, tearing it down to potentially clean the heatsink is slightly more challenging. To start, you will need to remove the four screws on the bottom to lift up the bottom plate. This will give you access to the two SODIMM slots, M.2 slot, and 2.5" drive bay. Most users won't have to go any further. It really is that quick and easy. For those wanting to go further, you will want to disconnect the SATA header from the bottom plate, which is much easier than messing with the ribbon cable.
Taking a closer look at the SSD, it seems GEEKOM opted for a Kingston 512 GB offering. This particular model is a PCIe 3.0 drive, and while not a high-performance offering, it is rated at 2400 MB/s reads and 1100 MB/s writes, which is more than adequate for this system and a massive upgrade over eMMC, which I have seen deployed in other mini-PCs. While I am glad to see GEEKOM include 16 GB of 3200 MHz DDR4 SODIMM memory, a single stick and thus single-channel dampens the mood, as does its operating frequency being limited to 2400 MHz. Dual-channel offers greater bandwidth, which is especially useful for the integrated graphics processor. Sure, it won't make the system feel much different, but for a few dollars more, it can deliver a sizable performance improvement in certain applications.
To remove the mainboard, you have a few things to take care of first. Start by removing the black screws holding the mainboard to the chassis. Once you have lifted the plastic shield from the WiFi module and gently removed the antenna wires while also unplugging the cable directly in front of it, remove the screws holding the mainboard to the chassis, and with that, only the final step remains.
To get to the heatsink and fan, you will need to gently spread the outer chassis while also wiggling the mainboard up and out because it is a very tight fit. However, once removed, you have successfully disassembled the system and can do whatever maintenance you deem necessary. As for the rather sizable heatsink, GEEKOM is using a fan from WINMA, model number EGC-70071F1-0AH. Sadly, I did not find any in-depth information on the fan. But judging by its performance and noise output on initial tests, it works just fine. More importantly, even though it was audible, averaging around 46 dBA, it wasn't intrusive.