Alienware X51 R3 vs. Lenovo ThinkCentre M900 Tower

Comparison and Differences

Alienware_X51_R3.jpg case front and back pannel

Lenovo_ThinkCentre_M900_Tower.jpg case front and back pannel

Model
Form factor	Small Gaming	Mini Tower
CPU options	Intel Gen6 i3/i5/i7;	Intel Gen6 i3/i5/i7; Celeron; Pentium;
Chipset	Z170	Q170
Dedicated GPU *	GeForce GTX 1650 Super	GeForce GTX 1660 Super
RAM	DIMM DDR3-2133	DIMM DDR4-2133
RAM slots	2	4
RAM speed	2133 MT/s	2133 MT/s
RAM max	32 GB	64 GB
USB ports	(4x) USB 3.0 Type A; (2x) USB-A 2.0; (2x) USB 3.1 Type A	(8x)USB-A 3.0;
Video ports	HDMI 1.4b;	(2x) DisplayPort 1.2; VGA;
Other ports	RJ45; Headset; Line-Out; Line-In; S/PDFI optical/analog;	RJ45; Hdph; (2x) Mic; Line-Out; Line-In; Serial;
Optional ports	N.A.	2x USB-A 2.0; Media card reader (USB 2.0); (2x) PS2; eSATA;
SATA ports	3	3
PCI slots	PCIe 3.0 x16;	PCIe 3.0 x16; PCIe 3.0 x1; PCIe 3.0 x16 (wired x4); M2 to PCI adapter (optional);
M.2 slots	N.A.	M.2 (WiFi/BT or PCI extension card)
Drive bays	(2x) 2.5in; 3.25in; 5.25in;	(2x) 2.5/3.5in; (2x) 5.25in;
PSU	180/240/330 W	ATX 250/400 W
Weight	5.49 kg (12.10 lbs	12.5 kg (27.5 lb)
Released	2015	2015
Manual	link	link
Price**	Check Price	Check 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 Lenovo ThinkCentre M900 Tower

Both computers, the Alienware X51 R3 and the Lenovo ThinkCentre M900 Tower, were released during the same year - 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 Lenovo ThinkCentre M900 Tower and will fit more easily under your desk.

Processor

The two models have the same generation of Intel processors. We think that the 6 generation of Intel Processors have enough power to execute all of the home and office tasks that most people will care to do.

Memory

The Lenovo ThinkCentre M900 Tower has 4 RAM slots while the Alienware X51 R3 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.

None of the desktops has an advantage when it comes to the speed of the RAM being used. Both models support RAM speeds of up to 2133. Additionally, if you will be needing a lot of RAM, better go for the Lenovo ThinkCentre M900 Tower 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 Lenovo ThinkCentre M900 Tower 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 Lenovo ThinkCentre M900 Tower comes with 2 ports, while the Alienware X51 R3 has only 1. If you are planning to use multiple monitors, the Lenovo ThinkCentre M900 Tower 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 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.

M.2 SSD interface allows you to transfer data with higher speeds compared to the old SATA interface. Unfortunately, neither the Alienware X51 R3, nor the Lenovo ThinkCentre M900 Tower has one. However, you can still use a SATA SSD drive which should give you satisfactory performance.

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 R3 comes with a decent 330 Watt PSU, but the Lenovo ThinkCentre M900 Tower has a more powerful one rated at 400 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.