Computer Circuit Boards for Different Parts: Motherboard, GPU PCB, etc.

Every computer is powered by a network of printed circuit boards (PCBs) that carry signals, regulate power, and connect critical components. Computer circuit boards act as the nervous system of the computer, ensuring smooth communication between the central processing unit (CPU), graphics card, memory, storage, and power supply.

One of the most common questions people ask is: What is the main circuit board inside the computer? The answer is simple: it is the motherboard, the largest and most essential PCB in any computer.

PCBONLINE is an OEM PCB manufacturer for high-quality PCB fabrication and assembly, including advanced BGA soldering for GPUs. In this article, we'll break down the main computer circuit boards, explain their functions, and highlight the manufacturing requirements. We will also discuss edge connectors and HDI technology, two key features that make computer PCBs reliable and powerful.

What Are the Main Computer Circuit Boards?

The motherboard is the main circuit board inside the computer, but it is not alone. A computer also contains other highly specialized PCBs, such as the GPU PCB, PSU PCB, SSD/HDD PCB, expansion card PCBs, and even smaller boards for fan and thermal management.

Motherboard: Heart of the Computer

The motherboard is the primary circuit board inside a computer. It holds and connects nearly every critical component, including:

• CPU socket – the slot that houses the processor.
• Memory slots – for RAM modules.
• Chipset – the hub for communication between CPU, GPU, storage, and peripherals.
• Power management circuits – regulating and distributing power.
• I/O ports – USB, Ethernet, HDMI, and audio connectors.
• Expansion slots (PCIe) – for GPUs, sound cards, and other devices.

The motherboard must balance signal integrity, power distribution, and mechanical durability. With modern CPUs and GPUs requiring massive data transfer rates, motherboards are designed with multi-layer HDI PCBs, using fine traces, microvias, and copper-filled via-in-pad structures to achieve high performance.

GPU PCB – Powering Graphics and AI

The GPU PCB (graphics processing unit printed circuit board) is the foundation for the graphics card. It carries:

• The GPU chip itself (usually packaged in BGA form).
• High-speed GDDR memory modules.
• A powerful voltage regulation module (VRM) for stable GPU power.
• PCIe edge connectors for interfacing with the motherboard.

Regarding GPU PCB assembly, the challenges in GPU PCB assembly are:

• BGA soldering voiding control below 25% is a must, and below 10% for reliability.
• High power density requires an advanced VRM layout.
• Thermal management to prevent overheating.

At PCBONLINE, we specialize in GPU PCB fabrication and assembly with IPC-A-610 Class 3 standards, offering reliable soldering, low voiding (<5%), and even BGA reballing services for refurbished GPUs.

PSU PCB – Power Supply Unit Circuit Board

The PSU PCB converts AC mains electricity into stable low-voltage DC power for the computer. It must handle:

• High voltages and currents.
• Power conversion circuits (AC-DC, DC-DC).
• Capacitors, transformers, and MOSFETs for energy regulation.

Because PSU PCBs deal with high currents, they require thicker copper layers (2–4 oz), wide traces, and strict isolation distances to ensure safety and efficiency.

SSD/HDD PCB – Storage Drive Circuit Boards

Storage devices like SSDs and HDDs also rely on their own dedicated PCBs.

SSD PCB: Hosts the NAND flash chips, controller, and power management ICs. These require fine-pitch BGA soldering for memory packages and high-speed signal routing.

HDD PCB: Contains the motor driver, cache memory, and firmware controller. Although simpler than SSDs, it must handle precise drive control and error correction.

With the rise of NVMe SSDs, storage PCBs now use HDI technology to accommodate high-speed PCIe interfaces.

Expansion Card PCBs

Expansion cards provide additional functionality to the computer, such as:

• Sound cards for high-quality audio.
• Networking cards (Ethernet, Wi-Fi).
• Specialized accelerator cards for AI or crypto-mining.

These PCBs must ensure reliable connectivity through edge connectors, which slide into the motherboard's PCIe slots.

Fan and Thermal Control PCBs

Cooling is vital for modern desktops, especially gaming PCs and workstations. Dedicated fan control PCBs regulate fan speed and monitor thermal sensors. Although small, these PCBs must be durable and reliable, as overheating can shorten component lifespan.

Edge Connectors – Reliable Computer PCB Connections

One of the most important requirements for computer circuit boards is edge connectors. They are the gold-fingered connectors at the edges of PCBs that plug into slots on the motherboard (such as GPU cards into PCIe slots).

Why are edge connectors important for computer circuit boards? Because they:

• Provide stable electrical connections for high-speed data transfer.
• Withstand repeated insertions and removals.
• Require durable surface finishing to prevent wear and oxidation.

At PCBONLINE, we have a dedicated hard gold plating line for edge connectors, direct gold salt purchasing qualification, environmental certifications, and advanced wastewater treatment systems. With these facilities and certifications, we ensure durable, high-reliability edge connectors for GPU PCBs, motherboards, and expansion cards.

HDI Technology in Computer Circuit Boards

A common characteristic of computer circuit boards, especially in mid-to-high-end systems, is the use of HDI (High-Density Interconnect) PCBs. HDI PCB features:

• Supports fine-pitch BGA packages (0.35–0.4 mm).
• Enables shorter signal paths for faster communication.
• Increases PCB density while keeping board size compact.

At PCBONLINE, our HDI PCB manufacturing provides:

• 4–64-layer PCB manufacturing.
• Any-layer interconnection for advanced designs.
• Perfect for motherboards, GPU PCBs, and high-performance computing boards.
• Class 3 assembly quality, ensuring reliability in critical devices.

With HDI, computers achieve faster speeds, lower power consumption, and higher reliability.

Partner with PCBONLINE for Computer Circuit Boards

PCBONLINE is a trusted one-stop PCB manufacturer and assembler for all types of computer circuit boards. We offer computer circuit board manufacturing and assembly from prototypes to mass production.

Founded in 2005, PBONLINE has two large advanced PCB manufacturing bases and one PCB assembly factory.

Whether you need a motherboard, GPU PCB, PSU PCB, or SSD PCB, PCBONLINE delivers professional, reliable, and cost-effective solutions. Send your inquiry by email to info@pcbonline.com to get a quote.

Conclusion

A desktop computer contains a motherboard, GPU PCB, PSU PCB, SSD/HDD PCB, expansion cards, and fan control boards. Reliable computer circuit boards require edge connectors, HDI technology, and fine-pitch BGA soldering. At PCBONLINE, we provide end-to-end PCB manufacturing and assembly, covering everything from motherboards and GPU PCBs to power supply boards and expansion cards for your custom needs.