Alienware Aurora R6 vs. Alienware X51 R2
Comparison and Differences
Differences between Alienware Aurora R6 and Alienware X51 R2
If you are looking for a more modern desktop, then you should go with the Alienware Aurora R6 which was released in 2016. The Alienware X51 R2 is older and entered production in 2013.
If you are looking for the smaller form factor the Alienware X51 R2 is the right one for you. It is smaller than the Alienware Aurora R6 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 Aurora R6 as it is running a newer generation CPU. This is not to say that Alienware X51 R2 is bad - it can still run some powerful CPUs, albeit being an older generation.
Memory
The Alienware Aurora R6 has 4 RAM slots while the Alienware X51 R2 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 Aurora R6 is using the faster 2666 MT/s RAM. The Alienware X51 R2 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 Aurora R6 as it has the ability to run 64 GB of RAM. The Alienware X51 R2 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 Aurora R6 has 15 USB ports. The Alienware X51 R2 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 Aurora R6, is that it has 2 USB 3.1 port(s) which allows transfer of up to 10Gb/s. Unfortunately, the Alienware X51 R2 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.
Unfortunately, only the Alienware X51 R2 has a DisplayPort. The Alienware Aurora R6 does not have one? Don't worry though, nowadays video adapters are cheap and you can get almost any combination of conversion types.
None of the models has an HDMI port. If your monitor supports only the HDMI interface, you will need to buy an adapter. Such adapters are cheap so nothing to worry about.
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 Alienware Aurora R6 is better equipped as it comes with 4 SATA slot(s), while the Alienware X51 R2 has 3 slot(s).
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 Aurora R6. Sadly, the Alienware X51 R2 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 Alienware X51 R2 comes with a decent 330 Watt PSU, but the Alienware Aurora R6 has a more powerful one rated at 850 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
