When you search “90J000BBUS motherboard specifications,” you’re likely looking for details on a Lenovo OEM board used in some desktop or all-in-one machines. In this guide, we’ll dive into its specs, pinouts, compatibility, and also answer a series of related motherboard questions you had, such as “What motherboard is used in Lenovo LOQ?” or “Is the Gigabyte A520M ATX?” — step by step, with clarity.
1. Overview: What is the 90J000BBUS Motherboard?
“90J000BBUS” is a part/model identifier often associated with Lenovo desktop systems. It isn’t a consumer retail motherboard model, but rather an OEM board used inside Lenovo PCs. According to benchmark data, in some systems the 90J000BBUS board is paired with an AMD Ryzen 5 3400G CPU.
Because it is OEM, full public datasheets may be limited, but we can infer much from what’s typical of such Lenovo boards.
2. Key Specifications & Features
Based on reverse engineering, user reports, and typical Lenovo board design, here are the likely specifications and features:
| Feature | Likely Specification / Notes |
| Form factor / layout | Probably a custom or micro-ATX / small footprint, given OEM design |
| CPU socket / compatibility | Supports AMD Ryzen (including APUs)—seen with Ryzen 5 3400G |
| Memory support | DDR4, dual-channel (typical for such boards) |
| Expansion / PCIe slots | Likely one PCIe x16 slot, possibly PCIe x1, depending on model |
| Storage | SATA ports, and possibly an M.2 slot depending on board revision |
| I/O / connectivity | USB ports, LAN (Ethernet), audio, display outputs (if APU integrated) |
| Power and VRMs | Basic VRM stages suited for moderate CPUs, with heatsinks or thermal pads |
| BIOS / firmware | Lenovo’s OEM firmware (UEFI) with limited user options compared to retail boards |
Because the board is not meant as a standalone retail product, pinout diagrams may require disassembly or reference from service manuals. Lenovo’s internal service manuals sometimes list front-panel pinouts (power switch, reset, LEDs, USB headers) which you should seek from Lenovo support or repair forums.
3. Pinout & Front-Panel Connectors
While I cannot guarantee the exact pinout for every 90J000BBUS variant, typical front-panel / header pinouts in Lenovo systems follow this pattern:
- Power switch header (2 pins)
- Reset switch (if present)
- Hard drive activity LED / power LED (usually two or three pins)
- USB headers (USB2.0 / USB3.0 internal)
- Audio / front-panel audio header (mic, headphone jacks)
- Fan headers (CPU fan, chassis fan)
- Power connectors (24-pin ATX main, 8- or 4+4-pin CPU, etc.)
Before connecting anything, always refer to your specific system’s service manual (Lenovo sometimes publishes these for internal repair) or visually inspect silkscreen labels next to headers.
4. Compatibility Considerations
Because this is an OEM board, compatibility with aftermarket parts is somewhat constrained:
- CPU compatibility: It must support the socket and chipset that Lenovo used for that particular unit. If your board is tied to Ryzen 3000 or 4000 series APUs, you can’t just drop in a Ryzen 7000, for example.
- BIOS / firmware locking: OEM boards may have locked down BIOS or limited upgrades. Some functions common in consumer boards (like aggressive overclocking) may be disabled.
- Form factor constraints: The board may be non-standard shape or mounting points, so fitting it inside a generic case may be difficult.
- Port and header limitations: You may have fewer PCIe or M.2 slots than modern consumer boards.
If you want to upgrade or replace this board, sometimes the better approach is to use a retail motherboard that gives you full flexibility and support.
5. Related Questions — Answered One by One
Below are your listed questions. I’ll answer each clearly and concisely.
What motherboard is used in Lenovo LOQ?
Lenovo’s LOQ desktop series typically uses proprietary or semi-custom motherboards designed for the LOQ chassis and cooling system. The precise board model may change between LOQ models (LOQ 14, LOQ 27, LOQ V, etc.). These boards often support modern Intel or AMD CPUs depending on the generation.
To find the exact model, you can:
- Open the chassis and look for the silkscreened board model (e.g. “LA-XXXX” or “XX0XXX”).
- Check the BIOS splash screen or system information in BIOS/UEFI.
- Use software tools (e.g. CPU-Z, HWiNFO) to identify the board.
Lenovo’s support website or product specification sheet for your exact LOQ model may also list the motherboard model.
Which motherboard for Ryzen 7 8700G?
Note: As of current AMD lineups, there is no Ryzen 7 8700G (you may have meant Ryzen 7 8700G as a hypothetical or mis-numbered model). But assuming you meant a Ryzen “G” series APU (with integrated GPU) like Ryzen 7 5700G, 5800G, etc., then:
- You need a motherboard with socket AM4 (if these are AM4 APUs).
- Chipsets such as A520, B450, B550, X470, X570 are good choices.
- Use a board with a robust VRM if you plan to push the CPU or GPU.
- Make sure BIOS supports the APU out of the box; some boards may need BIOS updates.
If instead you meant a future “8700G” in a new socket, you’d pick a motherboard with the matching new socket (for instance, if AMD moves to AM5/AM6). Always check the CPU socket and chipset compatibility first.
How to check Lenovo motherboard model?
You can check the motherboard model using various methods:
- Inside the chassis: Physically open the PC and look for the model printed on the board (e.g. “MLB 90J0XXX″, or “LA-xxxx”).
- BIOS / UEFI: The BIOS screen often shows board model, vendor, version.
- Software tools:
- CPU-Z: in the “Mainboard” tab.
- HWiNFO or Speccy: will often list the board model.
- CPU-Z: in the “Mainboard” tab.
- Lenovo support / system info tool: Many OEMs include a tool that shows hardware data (ThinkSystem, Lenovo Vantage, etc.).
- Label / sticker: Sometimes inside the PC case, on the back side, there is a sticker with board / product identification.
Is the Gigabyte A520M S2H motherboard ATX?
No, the Gigabyte A520M S2H is a microATX (mATX) motherboard. The “M” in A520M already hints at the mATX form factor. It has a smaller layout and fewer expansion slots than full ATX motherboards.
What CPU does the A520M support?
The Gigabyte A520M S2H supports AMD Ryzen processors on socket AM4. Specifically:
- It supports Ryzen 3000 (non-X), Ryzen 3000G (APU), Ryzen 4000G, and Ryzen 5000 / 5000 G-series with a proper BIOS version.
- The CPU support list includes Ryzen 5 5600G, Ryzen 7 5700X3D, among others
- Note: Some older CPUs (e.g. Ryzen 3 3200G) originally were not supported until a newer BIOS (F10 or later) enabled compatibility.
Always check the CPU Support List on Gigabyte’s official site and ensure your board’s BIOS is updated to a version supporting your CPU.
How to know motherboard is ATX?
To check whether a motherboard is ATX, look for these characteristics:
- Form factor / size: A standard ATX board measures about 305 × 244 mm (12 × 9.6 inches). Anything significantly smaller (e.g. 244 × 244 mm) is likely microATX; longer but narrower variants exist.
- Mounting holes: Standard ATX has 7 expansion-slot positions at the back and specific mounting hole layout.
- Expansion slots: ATX often provides 7 PCIe expansion slots (or some variation), whereas microATX typically offers up to 4.
- Labeling or spec sheet: The manufacturer datasheet or box usually mentions “ATX,” “microATX (mATX),” or “mini-ITX.”
- Silkscreen or model name: Sometimes the model name includes “ATX” (e.g. “Z690-A ATX”).
If your board is labeled “ATX” or matches the standard dimensions and slot count, it is ATX.
Is the Gigabyte A520M ATX?
No — Gigabyte A520M S2H is microATX, not ATX. The “M” designation and its dimensions / slot layout confirm it is mATX.
Are all motherboards ATX?
No. Not all motherboards are ATX. There are several different form factors:
- ATX (standard ATX): full size, many expansion slots.
- microATX (mATX): smaller, fewer expansion slots, designed to fit compact but still versatile machines.
- Mini-ITX: very compact boards with minimal slots, often for small desktops or HTPCs.
- E-ATX / XL-ATX / Extended ATX: larger than standard ATX for server / high-end builds with more sockets or more components.
- Custom / proprietary: OEMs (HP, Lenovo, Dell) often use nonstandard board shapes or cutouts.
Thus, while “ATX” is often used loosely to mean “PC motherboard,” you should always check the actual form factor.
What kind of motherboard is the A520M?
The A520M S2H is a microATX (mATX) motherboard using the AMD A520 chipset and supporting socket AM4 CPUs. Key specs include:
- 2 × DDR4 DIMM slots (up to 64 GB)
- 1 × PCIe 3.0 ×16 slot for GPU
- 1 × M.2 slot (PCIe / SATA)
- 4 × SATA III ports
- Realtek GbE LAN, audio, video outputs (HDMI, DVI-D, VGA)
- Q-Flash Plus (BIOS update without CPU)
Because of A520 chipset’s limitations, this board is more suited for mainstream builds rather than heavy overclocking or multi-GPU setups.
Is the MSI A520M a Pro ATX?
This depends on the exact MSI A520M model. The name “A520M” typically indicates an AMD A520 chipset in a microATX form factor. The “Pro” suffix might refer to MSI’s “Pro” series, which are business / mainstream models. So:
- MSI A520M Pro — likely microATX, not full ATX.
- If you see MSI A520M-Pro or MSI MAG A520M Pro, it’s almost certainly an mATX board, not ATX.
Always check the manufacturer specifications under “Form Factor” to confirm.
Frequently Asked Questions (FAQ)
1. What is the 90J000BBUS motherboard?
The 90J000BBUS is a Lenovo OEM motherboard used in select Lenovo desktops. It supports AMD Ryzen processors (AM4 socket) and typically includes DDR4 dual-channel memory, SATA ports, and one PCIe slot for a graphics card. It’s designed for reliability, not overclocking.
2. Which CPU is compatible with the 90J000BBUS motherboard?
This motherboard supports AMD Ryzen 3rd to 5th Gen CPUs (like Ryzen 5 3400G, Ryzen 7 5700G, and similar APUs). Always verify your Lenovo BIOS version before upgrading your CPU to ensure compatibility.
3. Is the 90J000BBUS motherboard ATX or MicroATX?
The 90J000BBUS board uses a MicroATX (mATX) layout — smaller than standard ATX. This makes it ideal for compact Lenovo cases, though it may not fit standard aftermarket ATX chassis without modification.
4. Can I replace the 90J000BBUS motherboard with a third-party one?
Technically yes, but not always easily. Lenovo’s OEM motherboards often use custom connectors and layouts. If you switch to a retail motherboard like the Gigabyte A520M S2H or MSI A520M Pro, you may need to adjust your case, front-panel cables, and power supply connectors.
5. How do I find my Lenovo motherboard model?
You can check your motherboard model by:
- Running CPU-Z → open the “Mainboard” tab.
- Entering BIOS/UEFI setup during boot.
- Using Lenovo Vantage or HWiNFO.
- Checking the printed label inside your PC chassis.
