Alienware Area 51 R5 vs. Dell Vostro 3900
Comparison and Differences
Differences between Alienware Area 51 R5 and Dell Vostro 3900
If you are looking for a more modern desktop, then you should go with the Alienware Area 51 R5 which was released in 2015. The Dell Vostro 3900 is older and entered production in 2014.
If you are looking for the smaller form factor the Alienware Area 51 R5 is the right one for you. It is smaller than the Dell Vostro 3900 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 Alienware Area 51 R5 as it is running a newer generation CPU. This is not to say that Dell Vostro 3900 is bad - it can still run some powerful CPUs, albeit being an older generation.
Memory
The Alienware Area 51 R5 has 4 RAM slots while the Dell Vostro 3900 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 Alienware Area 51 R5 is using the faster 3200 MT/s RAM. The Dell Vostro 3900 is slower by supporting RAM speeds of up to 1600 MT/s. Additionally, if you will be needing a lot of RAM, better go for the Alienware Area 51 R5 as it has the ability to run 64 GB of RAM. The Dell Vostro 3900 can do a bit less at max 16 GB. Most of the times, this should be sufficient for the majority of users.
Ports
In total the Alienware Area 51 R5 has 13 USB ports. The Dell Vostro 3900 is inferior in this regard and packs 8 USB ports. In any case, if you miss USB ports, you can always purchase a USB hub. What is nice about the Alienware Area 51 R5, is that it has 2 USB 3.1 port(s) which allows transfer of up to 10Gb/s. Unfortunately, the Dell Vostro 3900 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.
Nowadays, almost every new computer comes equipped with a DisplayPort. However, none of the devices being compared here has one. Don't worry though, DisplayPort adapters are very cheap and you can get virtually any combination of conversion types.
The Dell Vostro 3900 comes with an HDMI port, while the Alienware Area 51 R5 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 slots are located on the motherboard and it is where SSD, HDD and Optical Disk Drives are connected. Each of the two models being compared have 4 SATA slot(s). Keep in mind that having too few SATA slots might limit your options for connecting additional memory drives.
If you want the fastest transfer speeds for your SSD, an M.2 interface is crucial. Thus, if the M.2 SSD slot is a mandatory requirement for you, go with the Alienware Area 51 R5. Sadly, the Dell Vostro 3900 has no such slot, and you will be forced to use the SATA interface instead.
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 Dell Vostro 3900 comes with a decent 300 Watt PSU, but the Alienware Area 51 R5 has a more powerful one rated at 1500 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.