HP Pro Mini 400 G9 Desktop 64GB DDR5, 4TB SSD - Compact Business PC

In this review the HP Pro Mini 400 G9 is judged as a compact, business-focused desktop that prioritizes memory and storage capacity for multitasking and local data workloads. The standout reason to consider this configuration is the combination of 64GB DDR5 RAM and a 4TB PCIe M.2 SSD, which turns the small chassis into a serious productivity machine for users who need large local storage and responsive performance in office, lab, or point-of-sale environments.

Key Features

• Processor: The Intel Celeron G6900T provides steady basic compute for everyday office apps and web work without drawing much power.
• Large memory: 64GB of DDR5 RAM keeps many browser tabs, virtual machines, or business applications open at once with minimal swapping.
• Mass storage: The 4TB PCIe M.2 SSD delivers fast boot and application load times and ample space for large local files and archives.
• Multiple displays: Two DisplayPort 1.4 ports plus HDMI 2.1 let users run up to three monitors for spreadsheets, dashboards, or multi-window workflows.
• Modern connectivity: Built-in WiFi 6E, Bluetooth 5.3 and a Gigabit Ethernet port support both fast wireless and wired networking options.
• Front I/O convenience: High-speed front USB-A and USB-C ports, including a 20Gbps Type-C, simplify connecting external drives and peripherals.

Who It's For

The Pro Mini 400 G9 configured with 64GB RAM and a 4TB SSD is aimed at professionals who need a space-efficient desktop that does not compromise on local memory or storage: data analysts working with large datasets, developers running multiple local services, and small business owners who prefer on-site storage rather than cloud-only solutions.

It is not the best fit for users who need top-tier CPU performance for heavy video rendering or gaming, since the Celeron G6900T is an entry-level processor. Also, buyers seeking an all-in-one monitor and stand solution should note the PC stand is not included and must be purchased separately.

Pros & Cons

Pros

• Very large memory and storage in a compact mini desktop, enabling heavy multitasking and large local file storage.
• Three-monitor support via dual DisplayPort and HDMI provides flexible workstation layouts.
• Modern I/O and networking including WiFi 6E, Bluetooth 5.3, USB-C 20Gbps and multiple high-speed USB ports.

Cons

• Entry-level Intel Celeron CPU limits raw single-threaded performance for intensive compute tasks.
• PC stand is not included, so small-foorprint mounting or placement may require an extra purchase.

Specifications

Processor	Intel Celeron G6900T, 2 cores, 2.8 GHz base
Memory	Up to 64GB DDR5 RAM (this configuration 64GB)
Storage	Up to 4TB PCIe M.2 SSD (this configuration 4TB)
Graphics	Intel UHD Graphics 710
Operating System	Windows 11 Pro 64-bit, English
Networking	WiFi 6E, Bluetooth 5.3, 1x Ethernet (RJ-45)
Ports	Front: USB-A 10Gbps, USB-A 10Gbps (charging), USB-C 20Gbps, headset; Rear: 2x USB-A 5Gbps, 1x USB-A 10Gbps, 2x DisplayPort 1.4, 1x HDMI 2.1

Our Verdict

The HP Pro Mini 400 G9 with 64GB DDR5 and a 4TB PCIe SSD is an excellent choice for professionals who need a small desktop with unusually large local memory and storage. It delivers strong everyday performance, rich connectivity and triple-monitor support in a compact package, making it good value for office, lab, or kiosk use where CPU-bound tasks are not the primary need.

Frequently Asked Questions

Does this model include a keyboard and mouse?
The system ships with an HP black wired keyboard and mouse included in the package.

Can it run three monitors at once?
Yes; the desktop includes two DisplayPort 1.4 outputs and one HDMI 2.1 output for three-monitor setups.

Is a stand included for vertical placement?
No; the PC stand is not included and must be purchased separately if vertical mounting is required.