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Lenovo ThinkCentre M720s Desktop (Humbopeep)

Humbopeep Front
ArcaOS license type


This new Lenovo ThinkCentre M720s computer is compatible with ArcaOS. It features a Pentium Gold G5400 processor, 4 GB RAM, 500 GB hard drive and a DVD-Writer. The Intel UHD Graphics 630 on the motherboard produces the fastest graphics I have yet measured on an OS/2 machine.


These are some useful additions you can buy to customize this computer. If more customizations are needed see the section named Custom orders below.

CPU upgrade

The central processing unit (CPU) can be upgraded to the Intel Core i7 for faster processing and graphics.

CPU upgrade

Quebopeep CPU upgrade

CPU upgrade: $200.00 USD

PS/2 Ports

This computer has optional PS/2 ports, used for old keyboards. This one is tested with the 122-key keyboard used by 3270 and 5250 emulators.

PS/2 Ports

Humbopeep PS/2 Ports

PS/2 Ports: $50.00 USD

Parallel Port

This computer has an optional parallel port.

Parallel Port

Parallel Port

Parallel Port: $50.00 USD

IDE Card

This PCIe-X1 bus card provides an internal IDE connection. You can use this card with DaniS506.ADD to provide support for Parallel ATA (PATA) hard drives.

IDE Card

IDE Card

PCIe IDE Card: $75.00 USD

USB Floppy Drive

This external USB Floppy drive can be used to read and write 720K and 1.44M 3 1/2 inch floppy disks.

USB Floppy Drive

USB Floppy Drive

USB Floppy Drive: $50.00 USD

External WiFi

Using a travel router with a desktop can free you from a wired Ethernet connection. I use the Mango Travel Router to access local WiFi or my phone's hot spot. Mango comes with everything you need to connect to an access point.

Mango Travel Router

Mango Thumbnail

Mango Travel Router: $49.00 USD

In the past, I have also used a TP-Link AC750 Wireless Travel Router, an Asus RP-N12 Wireless N300 Range Extender, and a TP-Link Nano Router. I include a folder of URL links to the admin pages of each of these routers to make it easy to set up the first time.

Instructions and details about external WiFi: Travel Routers

Hard drive upgrade

The hard drive can be upgraded to a 2 TB drive. Either a hard disk or an SSD is available to upgrade.

Hard drive upgrade

Quebopeep hard drive upgrade
Storage type

Custom Orders

If you want to buy a customized version of this computer, fill out an order form and submit it to Blonde Guy. Blonde Guy will review your order and send you an invoice, payable using PayPal or any major credit card. If you prefer to pay by check, note that in the notes field of the order form, and I will e-mail you an invoice payable by check.

Enter the customizations you want on the computer in the notes portion of the order form.


Manufacturer: Lenovo
Model: ThinkCentre M720s Desktop
Model number: 10STCTO1WW
Year introduced: 2019
CPU: Intel(R) Pentium (TM) Gold G5400 CPU 3.7 GHz (2 cores)
RAM: 4.0 GB PC3-12800 1600MHz DDR3
Hard drive: 500 GB 3.5 inch SATA
Optional hard/solid state drive: 2000 GB SATA
Optical drive: LiteOn DS-8ACSH Internal DVD Drive
Network: Intel Gigabit Ethernet using MultiMac32-E1000E driver
Audio: HDA Intel PCH using Uniaud, USB Audio headphone out, microphone in
USB ports: 8 USB 3.0 ports (4 front, 4 back)
USB controllers: 1 XHCI for all built-in ports
Serial ports:1
PS/2 ports: 2 (optional)
Video ports: VGA, 2 DisplayPorts Internal slots: 2 PCIe-1, 1 PCIe-16 half height
Parallel port: 1 (optional)

Physical Dimensions

Height: 10.8 inches
Width: 3.9 inches
Depth: 11.9 inches
Weight: 9.4 lbs

Power Consumption

Power consumption is 19 Watts, measured with the computer is booted to the desktop and idle. In use, with all cores at 100% the computer can consume about 40 watts. This computer consumes 1 Watt if it's plugged in, but switched off.

Disk Layout

The disk is partitioned to provide a bootable operating system volume and a bootable installer. Space is left for addtional bootable volumes. User data is stored on a separate volume.

This is the layout for the 500 GB HD. The Air-Boot boot manager is installed to select the volume to be started.

Volume NameDisk FormatDrive LetterVolume SizeDisk Name
RecoveryFAT16 X:2,000 MBInternal
ArcaOS-FJFS F:10,001 MBInternal
Data-D JFS D:100,000 MBInternal

This is the layout for a 2 TB drive.

Volume NameDisk FormatDrive LetterVolume SizeDisk Name
RecoveryFAT16 X:2,000 MB2 TB SSD
ArcaOS-FJFS F:10,001 MB2 TB SSD
Data JFS D:1,857,718 MB2 TB SSD

ArcaOS version

ArcaOS 5.0.6 (Aug 31, 2020) is the version used for this installation.

Performance Benchmarks

This table reports the SysBench 0.9.5 benchmarks for this computer. You can download SysBench 0.9.5 here:

PM-Graphics-marks 275
CPU integer-marks 8413
CPU floating point-marks 596
DIVE-marks 9514
File I/O-marks 93531
Memory-marks 28253
Simultaneous I/O-marks 43
Disk I/O-marks 707

With an SSD installed, these are the benchmarks. SysBench does not correctly run Disk I/O-marks on SSD, so that benchmark is omitted. See File I/O-marks for comparitive information on disk performance.

PM-Graphics-marks 280
CPU integer-marks 8390
CPU floating point-marks 598
DIVE-marks 10012
File I/O-marks 203037
Memory-marks 28046
Simultaneous I/O-marks 62


Preloaded Software

Each Blonde Guy ArcaOS preloaded computer comes with a standard load of software. This page lists what is in the current pre-load. This list is updated over time to incorporate new essential OS/2 software as well as to keep up to date versions of existing software. When you receive your ArcaOS preloaded computer, you will have Blonde Guy's best installation of the latest OS/2 software.

Recovery DVD

The recovery DVD supplied is a bootable ArcaOS DVD with a backup of the hard drive as delivered. You can boot the machine from DVD, and perform maintenance functions. The maintenance folder is available on the recovery DVD. The factory backup is stored in the \Factory directory. The backups are simple zip files. You can use 7z or unzip to extract some or all of the files in a backup.

Build Notes

This section documents what I did to get this computer to work under ArcaOS. It is intended to show what goes into this computer, and also as a guide to the user who wants to build it himself.

BIOS changes

After powering up the computer, press F1 to enter the BIOS. There is no BIOS password.

Reliability is improved by disabling Hyperthreading in BIOS. The settings is found under CPU on the BIOS screens.

Installing ArcaOS

Lenovo systems like this one come with Windows 10 pre-loaded. The ArcaOS installer may not see the disk at all with default settings. This is a feature to protect Windows from being overwritten. Windows is normally installed to a GPT format hard drive, while ArcaOS is installed to a MBR format hard disk. A hard drive can only be one format, so in order to install ArcaOS, I need to wipe the hard drive.

How to install ArcaOS over Windows 10

When preparing a hard drive of over 500 GB, I needed to change the geometry. This can be done automatically by running Disk Utility from the ArcaOS installation DVD.

Disk Utility

** Problems were detected in your disk layout. The problems are listed below.

We may be able to fix these problems for you; see below for details. Please note, however, that we cannot be held liable for any damage or lost data that may result from this action.

The following problems were found:

* There is no valid partition table on the disk. A new partition table must be written before this disk can be used.The disk appears to contain no data, so this operation should be harmless. However, if it does contain data which OS/2 has failed to detect, any such data will be lost if you proceed.

The above problem(s) must be fixed before you can use this disk with OS/2.

If I have fixed the disk using DiskUtility or other procedure, then I run Disk Utility again. If it says "No problems found.", then I proceed to lay out the disk paritioning that I want using "Manage Volumes (Graphical)."

Driver Notes

The SATA hardware is supported by the OS2AHCI driver. This works with native command queueing. The parameters for OS2AHCI are as follows:


The ethernet port on the computer is supported by the Multimac32 driver. The network interface has been set up to configure automatically.

The audio hardware is the HDA Intel PCH on the motherboard, which uses an Realtek ALC233 mixer. The UniAud driver was built by Paul Smedley in Feb, 2021 and posted on OS/2 World. USB audio is installed as well, and works as tested witha SYBA USB Stereo Sound Adapter.

Arca Noae USB 3.0 driver loads and works with some limitations.

DOS Full Screen works. DOS Window does not. But if you press Alt-Home in DOS Full Screen, you get a functional DOS Window. DOS compatibility was tested using Lotus 1,2,3 DOS.

ArcaOS 5.0.5 and later has support for rebooting, but the support must be activated by creating or modifying OS2LDR.CFG in the root of the boot drive. Add the following line:


I do this when installing. At the first chance for a reboot, I go to system management and create the OS2LDR.CFG file as noted above.

I tested video using a Dell monitor with 1920 x 1200 resolution and a VGA connector. A more modern monitor would use the DisplayPort connector. The maximum resolution for DisplayPort is 4096 x 2304, I did not verify this.


I bought the first M720s new from Lenovo. These pictures are of the unboxing.


humbopeep Unboxing

Unboxing 2

humbopeep Unboxing 2


humbopeep Front


humbopeep Rear

Interior shot with tool-free drive bays.

humbopeep Interior

Another Interior shot

This shows the Startek USB 2.0 PCIe card installed. This card is no longer needed because the new ArcaOS driver provides support for the USB 3.0 hardware on the Motherboard.

humbopeep Interior 2

Yet another interior shot

This shows the PS/2 internal extension cable during installation. I have since learned to install the cable without removing the CPU and fan.

humbopeep Interior 3