Motherboard & Chipset: The Nervous System

"The Socket Fits, So Why Doesn't It Work?"

I had an absurd experience while upgrading my Intel CPU. The socket shape (LGA 1700) was identical, but the motherboard wouldn't recognize the new CPU. It turned out the 'Chipset' didn't support it.

"Wait, isn't it just a board that connects wires?" Until then, I thought a motherboard was just a 'plate to plug parts into'. But the motherboard was a 'Nervous System', and the chipset was the 'Spinal Cord'.

At first, I had this mindset: "Why pay for an expensive motherboard? The CPU does all the work anyway." Then I plugged an i9-13900K into an H610 board, and my server shut down from overheating. That's when I learned: A weak body kills even a genius brain.

1. Motherboard: City Infrastructure

The Motherboard is the Infrastructure of the computer city—roads, power grid, communication network. CPU, RAM, GPU, SSD—everyone talks over this board. I used to think it was "just a plate that connects stuff", but after swapping boards myself, I felt how critical it really is.

1.1. VRM (Voltage Regulator Module): The Substation

The VRM is the motherboard's Substation. It steps down the 12V from the PSU to around 1V that the CPU can digest, and keeps the voltage stable. If this is weak, the CPU throttles or, in the worst case, dies.

When I plugged an i9-13900K into an H610 board, the CPU was fine but the VRM heatsink got so hot I couldn't touch it. Turns out H610 has a 4+1 Phase VRM, while the i9-13900K needs at least 12+1 Phase. Eventually, the VRM died from overload, and I had to replace the whole board.

VRM Phase is a structure that splits power delivery into multiple lines for distributed supply. 12+1 Phase means 12 lines for the CPU, 1 line for integrated graphics. More phases = better power distribution = less heat = more overclocking headroom.

For example, delivering 100W:

• 4 Phase: Each line handles 25W → Hot
• 12 Phase: Each line handles 8.3W → Cool

Overclockers hunt for Z790 boards because they have generous VRM phases like 18+1, 20+2.

1.2. PCIe Slots: The Highways

PCIe (PCI Express) slots are the motherboard's Highways. GPUs, NVMe SSDs, sound cards—anything that needs high-speed data transfer plugs in here.

PCIe uses Lanes to denote speed. x1, x4, x8, x16—the higher the number, the wider the highway.

PCIe Version	x1	x4	x8	x16
PCIe 3.0	985 MB/s	3.9 GB/s	7.9 GB/s	15.8 GB/s
PCIe 4.0	1.97 GB/s	7.9 GB/s	15.8 GB/s	31.5 GB/s
PCIe 5.0	3.94 GB/s	15.8 GB/s	31.5 GB/s	63 GB/s

GPUs typically use x16 slots. NVMe SSDs use M.2 slots (x4). I once plugged my GPU into the second slot, and performance tanked by half. Turns out the second slot was x8. The first slot is usually CPU-direct x16; the rest are x8 or x4 routed through the chipset.

1.3. Form Factor: Size vs Expandability Trade-Off

Motherboard sizes follow standards. ATX → mATX (Micro ATX) → ITX (Mini ITX), in descending order.

Form Factor	Size (mm)	PCIe Slots	RAM Slots	Use Case
ATX	305 x 244	7	4	Desktop, Workstation
mATX	244 x 244	4	4	Budget Desktop
ITX	170 x 170	1	2	Small PC, NAS

At first I thought, "Smaller is better, right? Smaller case too." But after using an ITX board, I felt the lack of expandability suffocating me. One GPU and you're done. No sound card, no capture card. RAM maxes out at 64GB (32GB x 2) with only 2 slots.

ATX, on the other hand, has room for 2 GPUs, 3 NVMe SSDs, 1 sound card, etc. But the case is big and heavy.

I settled on mATX. The sweet spot between size and expandability.

1.4. Server Motherboards: Dual Socket, ECC, IPMI

Server motherboards are on another level compared to consumer desktops. Dual Socket means you can plug in 2 CPUs. Literally double the cores.

For example, plug in two Intel Xeon Gold 6342 (24-core) → total 48 cores, 96 threads. Used in database servers or AI training clusters where core count is king.

Server boards also support ECC RAM (Error-Correcting Code RAM). ECC automatically detects and corrects memory errors. Regular RAM just ignores bit flips; ECC catches them.

Banks, hospitals, cloud providers—anywhere data integrity is critical—require ECC RAM. But it costs 2x more than regular RAM.

Server boards also have IPMI (Intelligent Platform Management Interface) or BMC (Baseboard Management Controller). This lets you remotely power on the server, configure BIOS, and view the screen without being physically there. Essential when your server sits in a datacenter rack.

2. Chipset: The Traffic Control Center

So what is the Chipset? (Z790, B760, etc.) It's the Traffic Control Center or Spinal Cord of the system.

The CPU is too noble and busy to talk to every single component. It only directly handles the VIPs: RAM and the main GPU. The chipset collects data from the peasants (USB, Sound, SATA, LAN) and batches it up for the CPU.

2.1. Northbridge & Southbridge: The Old Days

Back in the 2000s, motherboards had 2 chipsets.

• Northbridge: Managed CPU, RAM, GPU. Sat next to the CPU for high-speed ops.
• Southbridge: Managed slower devices like USB, SATA, sound, LAN. Sat on the bottom.

Northbridge had to be close to the CPU, so it ran hot and had a big heatsink. I remember my 2005 motherboard had a fan on the Northbridge heatsink.

Around 2008, Intel integrated the memory controller into the CPU, and Northbridge vanished. Now the CPU talks directly to RAM, so no need for a middleman chip. Modern motherboards have just 1 chipset, which is basically the old Southbridge.

Intel calls it PCH (Platform Controller Hub). AMD just calls it Chipset.

2.2. Chipset Tiers: Z > B > H

Intel chipsets have tiers. (e.g., Z790, B760, H610) The letter is the tier, the number is the generation.

Chipset	Overclocking	PCIe Lanes	USB	SATA	Price	Target User
Z (High-end)	Yes	Many (28)	Many	8	$$$$	Gamers, Overclockers
B (Mid-range)	No	Medium (12)	Medium	6	$$	General Users
H (Budget)	No	Few (6)	Few	4	$	Office, Budget Builds

At first I thought, "I'm not overclocking, why pay for Z?" But after using them, I learned PCIe lane count matters.

For example, if you plug in:

• 2x NVMe SSDs (x4 each) + 1x GPU (x16) + 1x Sound Card (x1)
• Total lanes needed: x4 + x4 + x16 + x1 = 25 lanes
• H610 only has 6 lanes → Some devices downgrade to x1 or get disabled entirely
• Z790 has 28 lanes → Everything runs at full speed

I settled on B760. No overclocking, but I need 2 SSDs + 1 GPU.

2.3. CPU Lanes vs Chipset Lanes

PCIe lanes split into CPU-direct lanes and Chipset lanes.

For Intel 13th Gen (Raptor Lake):

• CPU Lanes: 20 (x16 GPU + x4 NVMe)
• Chipset Lanes: Z790 has 28, B760 has 12, H610 has 6

CPU lanes are direct (fast). Chipset lanes go through the DMI (Direct Media Interface) link between CPU and chipset (slower). DMI is x8 speed, so all chipset-connected devices share this x8 link.

For example, if you plug 3 NVMe SSDs into the chipset:

• x4 + x4 + x4 = 12 lanes used
• But DMI is only x8
• All 3 SSDs reading simultaneously → bandwidth bottleneck

Best practice: Plug the fastest SSD into the CPU-direct M.2 slot, the rest into chipset slots.

3. Checking Motherboard Structure with lspci

On Linux, use lspci to view PCIe devices.

lspci -tv

Example output:

-[0000:00]-+-00.0  Intel Corporation 13th Gen Core Processor Host Bridge/DRAM
           +-01.0-[01]----00.0  NVIDIA Corporation GA102 [GeForce RTX 3090]
           +-06.0-[02]----00.0  Samsung Electronics Co Ltd NVMe SSD Controller PM9A1
           +-14.0  Intel Corporation Alder Lake-S PCH USB 3.2 Gen 2x2 Controller
           +-17.0  Intel Corporation Alder Lake-S PCH SATA Controller
           +-1f.0  Intel Corporation Z690 Chipset LPC/eSPI Controller
           \-1f.3  Intel Corporation Alder Lake-S HD Audio Controller

What this shows:

• 00.0: CPU (Host Bridge)
• 01.0: GPU (NVIDIA RTX 3090) → CPU-direct x16 slot
• 06.0: NVMe SSD (Samsung PM9A1) → CPU-direct M.2 slot
• 14.0: USB Controller → Chipset
• 17.0: SATA Controller → Chipset
• 1f.0: Chipset (Z690 PCH)
• 1f.3: Audio → Chipset

The GPU and first NVMe connect directly to the CPU. USB/SATA/Audio route through the chipset.

4. Checking Motherboard Info with dmidecode

dmidecode reads hardware info from the BIOS.

sudo dmidecode -t baseboard

Example output:

Handle 0x0002, DMI type 2, 15 bytes
Base Board Information
	Manufacturer: ASUSTeK COMPUTER INC.
	Product Name: ROG MAXIMUS Z790 HERO
	Version: Rev 1.xx
	Serial Number: 231234567890
	Asset Tag: Default string
	Features:
		Board is a hosting board
		Board is replaceable
	Location In Chassis: Default string
	Chassis Handle: 0x0003
	Type: Motherboard

This shows my motherboard is the ASUS ROG MAXIMUS Z790 HERO.

For VRM info, use sensors:

sensors

Example output:

nct6798-isa-0290
Adapter: ISA adapter
in0:                      440.00 mV (min =  +0.00 V, max =  +1.74 V)
in1:                        1.01 V  (min =  +0.00 V, max =  +0.00 V)  ALARM
in2:                        3.34 V  (min =  +0.00 V, max =  +0.00 V)  ALARM
...
VRM Temp:                  +42.0°C  (high = +80.0°C, hyst = +75.0°C)
                                    (crit = +100.0°C)

VRM Temp at 42°C is healthy. Over 80°C is danger zone.

5. Bandwidth Bottleneck

Once I understood all this, I started seeing PCIe Lanes everywhere. I bought a board boasting "4 NVMe Slots", but when I filled them, speeds tanked by half.

Turns out the chipset has a fixed Lane Budget. Too many SSDs → Chipset says, "Traffic jam. Everyone slow down." Expensive boards (Z-Series) cost more because they have wider roads (More Lanes).

My situation:

• M.2 slots: Slot 1 is CPU-direct (x4), Slots 2~4 route through chipset (x4 each)
• B760 board: 12 chipset lanes
• I plugged in 4 NVMe SSDs
• Result: Slots 2~4 downgraded from x4 → x2 (half speed)

The motherboard manual had a table like this:

M.2 Slots Used	Slot 1	Slot 2	Slot 3	Slot 4
1 SSD	x4	-	-	-
2 SSDs	x4	x4	-	-
3 SSDs	x4	x4	x2	-
4 SSDs	x4	x2	x2	x2

Chipset lanes get divided when there's not enough to go around. Z790 boards with 28 chipset lanes can run all 4 at x4.

6. Summary: Strong Body for Strong Brain

If the CPU is the 'Brain', the Motherboard and Chipset are the 'Body'. Even a genius brain (i9-13900K) can't perform in a frail body.

After understanding motherboards and chipsets, I finally got why "Skimping on the motherboard" is a dangerous game. The motherboard isn't just a plate—it's the nervous system, traffic network, and power grid all in one. The chipset isn't just "Z or B"—it determines how many high-speed devices I can actually use.

The history of Northbridge/Southbridge splitting into a unified PCH after CPUs integrated memory controllers was fascinating. Once I grasped VRM Phases, I accepted why high-end boards matter even without overclocking. Server boards with dual sockets, ECC RAM, and IPMI—I know I'll need these features when I rack servers in a datacenter someday.

Running lspci and dmidecode to see my actual motherboard structure made the theory click into reality for me.