Dell XPS 8940 vs. HP ProDesk 600 G3 SFF
Comparison and Differences
Differences between Dell XPS 8940 and HP ProDesk 600 G3 SFF
If you are looking for the smaller form factor the HP ProDesk 600 G3 SFF is the right one for you. It is smaller than the Dell XPS 8940 and will fit more easily under your desk.
Usually the newer the generation of the CPU, the better the performance and efficiency is. If your budget allows it, you should go with the Dell XPS 8940 as it is running a newer generation CPU. This is not to say that HP ProDesk 600 G3 SFF is bad - it can still run some powerful CPUs, albeit being an older generation.
Both models have have equal amount of ram slots (4 RAM). Usually two RAM slots are more than enough for most cases. However, the count should be taken into account when planning how much and what combination of RAM you are going to need for your system.
The Dell XPS 8940 is using the faster 2666 MT/s RAM. The HP ProDesk 600 G3 SFF is slower by supporting RAM speeds of up to 2400 MT/s. Additionally, if you will be needing a lot of RAM, better go for the Dell XPS 8940 as it has the ability to run 128 GB of RAM. The HP ProDesk 600 G3 SFF can do a bit less at max 64 GB. Most of the times, this should be sufficient for the majority of users.
In total the HP ProDesk 600 G3 SFF has 11 USB ports. The Dell XPS 8940 is inferior in this regard and packs 10 USB ports. In any case, if you miss USB ports, you can always purchase a USB hub. What is nice about the Dell XPS 8940, is that it has 1 USB 3.1 port(s) which allows transfer of up to 10Gb/s. Unfortunately, the HP ProDesk 600 G3 SFF has no such port, thus restricting your transfer speeds significantly. For people who want to use external drives on regular basis, this might be an issue.
DisplayPort is crucial for any desktop machine. It is good to see that both models are featuring DisplayPorts. However, the HP ProDesk 600 G3 SFF comes with 2 ports, while the Dell XPS 8940 has only 1. If you are planning to use multiple monitors, the HP ProDesk 600 G3 SFF is the better choice.
The Dell XPS 8940 comes with an HDMI port, while the HP ProDesk 600 G3 SFF does not support the interface. Of course missing HDMI port is something that can be easily fixed with a good adapter (e.g. DisplayPort to HDMI).
SATA ports are placed on the system board and it is where you connect your HDD, SSD and Optical Disk Drives. More SATA slots will allow you to have more drives running at the same time. In this regard the Dell XPS 8940 is better equipped as it comes with 3 SATA slot(s), while the HP ProDesk 600 G3 SFF has 2 slot(s).
When your goal is to have the fastest SSD transfer speeds, an M.2 interface is crucial. Thus, it is good that both models have M.2 SSD slots. Today M.2 SSDs are not much more expensive than the average SATA drives, so it really does not make sense to invest in SATA drives anymore.
Make sure that the available M.2 slot supports the PCIe (also called NVMe) interface. This is important as there are M.2 slots which support only the inferior SATA III interface. For comparison, the SATA III interface has max speeds of 6Gb/s, while the PCIe 3.0 x4 will support speeds up to 32Gb/s!
Having a Power Supply Unit with high power rating is important, if you are going to use components which require extra power. The HP ProDesk 600 G3 SFF comes with a decent 180 Watt PSU, but the Dell XPS 8940 has a more powerful one rated at 500 Watts. Choosing either one depends on your specific requirements and use case. Also don't forget that some models might have more than one PSU option - try to always get the most powerful one, especially if you plan to upgrade to a powerful GPU.