Dell OptiPlex 7040 MT vs. HP ProDesk 400 G3 Mini
Comparison and Differences
Differences between Dell OptiPlex 7040 MT and HP ProDesk 400 G3 Mini
If you are looking for a more modern desktop, then you should go with the HP ProDesk 400 G3 Mini which was released in 2016. The Dell OptiPlex 7040 MT is older and entered production in 2015.
If you are looking for the smaller form factor the HP ProDesk 400 G3 Mini is the right one for you. It is smaller than the Dell OptiPlex 7040 MT and will fit more easily under your desk.
Processor
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 HP ProDesk 400 G3 Mini as it is running a newer generation CPU. This is not to say that Dell OptiPlex 7040 MT is bad - it can still run some powerful CPUs, albeit being an older generation.
Memory
The Dell OptiPlex 7040 MT has 4 RAM slots while the HP ProDesk 400 G3 Mini has only 2 slot(s). This is not something to worry about. Just make sure you take it into consideration when planning how much RAM you are going to use.
The HP ProDesk 400 G3 Mini is using the faster 2400 MT/s RAM. The Dell OptiPlex 7040 MT is slower by supporting RAM speeds of up to 2133 MT/s. Additionally, if you will be needing a lot of RAM, better go for the Dell OptiPlex 7040 MT as it has the ability to run 64 GB of RAM. The HP ProDesk 400 G3 Mini can do a bit less at max 32 GB. Most of the times, this should be sufficient for the majority of users.
Ports
In total the Dell OptiPlex 7040 MT has 10 USB ports. The HP ProDesk 400 G3 Mini is inferior in this regard and packs 6 USB ports. In any case, if you miss USB ports, you can always purchase a USB hub. None of the desktop models has a USB 3.1 port (10Gb/s), so if you need a fast connection to your peripherals, like external Solid State Drive, you will need to look elsewhere.
DisplayPort is crucial for any desktop machine. It is good to see that both models are featuring DisplayPorts. However, the Dell OptiPlex 7040 MT comes with 2 ports, while the HP ProDesk 400 G3 Mini has only 1. If you are planning to use multiple monitors, the Dell OptiPlex 7040 MT is the better choice.
The Dell OptiPlex 7040 MT comes with an HDMI port, while the HP ProDesk 400 G3 Mini 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 OptiPlex 7040 MT is better equipped as it comes with 4 SATA slot(s), while the HP ProDesk 400 G3 Mini has 1 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!
Power Supply
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 400 G3 Mini comes with a decent 90 Watt PSU, but the Dell OptiPlex 7040 MT has a more powerful one rated at 240 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.
Motherboard
