Alienware X51 R3 vs. Dell OptiPlex 3090 SFF

Comparison and Differences

Alienware_X51_R3.jpg case front and back pannelDell_OptiPlex_3090_SFF.jpg case front and back pannel
Model
Form factorSmall GamingSmall
CPU optionsIntel Gen6 i3/i5/i7;Intel Gen 10 i3/i5/i7/i9; Pentium
ChipsetZ170Q470
Dedicated GPU *GeForce GTX 1650 SuperAMD Radeon RX 6400 Low Profile
RAMDIMM DDR3-2133DIMM DDR4-2666
RAM slots22
RAM speed2133 MT/s2666 MT/s
RAM max32 GB64 GB
USB ports(4x) USB 3.0 Type A; (2x) USB-A 2.0; (2x) USB 3.1 Type A(4x) USB-A 2.0; (4x) USB-A 3.0;
Video portsHDMI 1.4b;Display Port 1.4a; HDMI 1.4b;
Other portsRJ45; Headset; Line-Out; Line-In; S/PDFI optical/analog;RJ45; Audio; Line-Out/In;
Optional portsN.A.HDMI 2.0b/Displayport/VGA;
SATA ports32
PCI slotsPCIe 3.0 x16;PCIe 3.0 x16; (2x) PCIe 3.0 x1;
M.2 slotsN.A.M.2 2230/2280 (PCIe 4.0 x4, NVMe); M.2 2230 (WiFi/BT)
Drive bays(2x) 2.5in; 3.25in; 5.25in;3.5in; 2.5in; 5.25in (slim);
PSU180/240/330 W200 W
Weight5.49 kg (12.10 lbs5.10 kg (11.25 lb)
Released20152021
Manuallinklink
Price**Check PriceCheck Price

** As an Amazon associate we earn from qualifying purchases.
* Dedicated GPU warning: Check if your particular power supply model has enough power. Additionally some PSUs don't come with an auxiliary PCIe power connector and you may need to buy a SATA to PCIe power adapter.

Differences between Alienware X51 R3 and Dell OptiPlex 3090 SFF

If you are looking for a more modern desktop, then you should go with the Dell OptiPlex 3090 SFF which was released in 2021. The Alienware X51 R3 is older and entered production in 2015.

Both models have the same form factor, meaning reoughtly they have the same phiysical size and form.

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 3090 SFF 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 3090 SFF 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 3090 SFF 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 3090 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 Dell OptiPlex 3090 SFF comes with 2 ports, while the Alienware X51 R3 has only 1. If you are planning to use multiple monitors, the Dell OptiPlex 3090 SFF is the better choice.

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 X51 R3 is better equipped as it comes with 3 SATA slot(s), while the Dell OptiPlex 3090 SFF has 2 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 Dell OptiPlex 3090 SFF. 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 3090 SFF comes with a decent 200 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.

Motherboard

Alienware_X51_R3_motherboard.jpg motherboard layoutDell_OptiPlex_3090_SFF_motherboard.jpg motherboard layout