Alienware X51 R3 vs. Dell OptiPlex 3080 MT
Comparison and Differences
Differences between Alienware X51 R3 and Dell OptiPlex 3080 MT
If you are looking for a more modern desktop, then you should go with the Dell OptiPlex 3080 MT which was released in 2020. The Alienware X51 R3 is older and entered production in 2015.
If you are looking for the smaller form factor the Alienware X51 R3 is the right one for you. It is smaller than the Dell OptiPlex 3080 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 Dell OptiPlex 3080 MT as it is running a newer generation CPU. This is not to say that Alienware X51 R3 is bad - it can still run some powerful CPUs, albeit being an older generation.
Memory
Both models have have equal amount of ram slots (2 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 OptiPlex 3080 MT is using the faster 2666 MT/s RAM. The Alienware X51 R3 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 3080 MT as it has the ability to run 64 GB of RAM. The Alienware X51 R3 can do a bit less at max 32 GB. Most of the times, this should be sufficient for the majority of users.
Ports
Both models have the same amount of USB ports for total count of 8. If this is not enough, using a USB hub is always a viable option. What is nice about the Alienware X51 R3, is that it has 2 USB 3.1 port(s) which allows transfer of up to 10Gb/s. Unfortunately, the Dell OptiPlex 3080 MT 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.
The DisplayPort is usually the more popular video port used with desktops and laptops, while the HDMI is used predominantly in consumer electronics. That's why, it is good to see that both of the models come with a DisplayPort.
The Dell OptiPlex 3080 MT comes with an HDMI port, while the Alienware X51 R3 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 3 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 Dell OptiPlex 3080 MT. Sadly, the Alienware X51 R3 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 OptiPlex 3080 MT comes with a decent 260 Watt PSU, but the Alienware X51 R3 has a more powerful one rated at 330 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.