HP ProDesk 400 G6 SFF vs. Lenovo ThinkCentre M900 Tower

Comparison and Differences

HP_ProDesk_400_G6_SFF.jpg case front and back pannel

Lenovo_ThinkCentre_M900_Tower.jpg case front and back pannel

Model
Form factor	Small	Mini Tower
CPU options	Intel Gen8&9 i3/i5/i7; Celeron; Pentium;	Intel Gen6 i3/i5/i7; Celeron; Pentium;
Chipset	B360	Q170
Dedicated GPU *	GeForce GT 1030 Low Profile	GeForce GTX 1660 Super
RAM	DIMM DDR4-2666	DIMM DDR4-2133
RAM slots	2	4
RAM speed	2666 MT/s	2133 MT/s
RAM max	64 GB	64 GB
USB ports	(4x)USB-A 3.0; (4x)USB-A 2.0;	(8x)USB-A 3.0;
Video ports	DisplayPort; VGA;	(2x) DisplayPort 1.2; VGA;
Other ports	RJ45; Headset; Line-In; Line-Out;	RJ45; Hdph; (2x) Mic; Line-Out; Line-In; Serial;
Optional ports	SD card reader; Serial; Serial and (2x) PS2; DP/HDMI/VGA/USB-C;	2x USB-A 2.0; Media card reader (USB 2.0); (2x) PS2; eSATA;
SATA ports	2	3
PCI slots	PCIe 3.0 x16; PCIe 3.0 x1 ;	PCIe 3.0 x16; PCIe 3.0 x1; PCIe 3.0 x16 (wired x4); M2 to PCI adapter (optional);
M.2 slots	M.2 2280/2230 M-key (PCIe x4); M.2 2230 (WiFi/BT)	M.2 (WiFi/BT or PCI extension card)
Drive bays	(2x) 2.5/3.5in; 5.25in (slim);	(2x) 2.5/3.5in; (2x) 5.25in;
PSU	180 W	ATX 250/400 W
Weight	4.6 kg (10.14 lb)	12.5 kg (27.5 lb)
Released	2019	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 HP ProDesk 400 G6 SFF and Lenovo ThinkCentre M900 Tower

If you are looking for a more modern desktop, then you should go with the HP ProDesk 400 G6 SFF which was released in 2019. The Lenovo ThinkCentre M900 Tower is older and entered production in 2015.

If you are looking for the smaller form factor the HP ProDesk 400 G6 SFF is the right one for you. It is smaller than the Lenovo ThinkCentre M900 Tower 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 HP ProDesk 400 G6 SFF as it is running a newer generation CPU. This is not to say that Lenovo ThinkCentre M900 Tower is bad - it can still run some powerful CPUs, albeit being an older generation.

Memory

The Lenovo ThinkCentre M900 Tower has 4 RAM slots while the HP ProDesk 400 G6 SFF 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 HP ProDesk 400 G6 SFF is using the faster 2666 MT/s RAM. The Lenovo ThinkCentre M900 Tower is slower by supporting RAM speeds of up to 2133 MT/s. In addition, you will be able to install the same amount of RAM in both models, and most probably 64 GB of RAM will be enough for most people. However, if you will be needing more RAM, make sure to check other desktop models too.

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. None of the desktop models has a USB 3.1 port (10Gb/s), so if you need a fast connection to your peripherals, like external Solid State Drive, you will need to look elsewhere.

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 HP ProDesk 400 G6 SFF 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 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 Lenovo ThinkCentre M900 Tower is better equipped as it comes with 3 SATA slot(s), while the HP ProDesk 400 G6 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 HP ProDesk 400 G6 SFF. Sadly, the Lenovo ThinkCentre M900 Tower 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 HP ProDesk 400 G6 SFF comes with a decent 180 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.