Turbo Frequency and Power Consumption

I use a PicoPSU-like solution with a 120W external adapter. Sometimes the i5-9400F PC consumes up to 96W. I feel uncomfortable about it and decide to lower power consumption by setting a new turbo frequency limit.

Turn Off LED on msi Motherboard

Table of Contents

1. Quick Guide
2. Install msi-rgb
3. Turn Off Immediatedly
4. Turn Off on Start
5. Turn Off After Resume
6. Reference

Quick Guide

1. Get and install nagisa’s msi-rgb utlity for msi motherboards.
2. OpenRGB is an alternative solution and supports more motherboards.
3. Turn off by running ‘sudo /home/amigo/msi-rgb/target/release/msi-rgb -x 00000000 00000000 00000000‘.
4. Use crontab to turn off after boot.
5. Create a shell script in /lib/systemd/system-sleep/ to turn off after resume.

The Max Power for an ATX 4-Pin CPU Power Connector is 216W

Because the i5-9400F consumes 80W at-wall while loading 300 tabs in Chrome, which is a huge jump from 30W at idle, I want to know if it is safe using the only 4-pin CPU power connector on Gigabyte H310M S2V 2.0 (rev. 1.0).

I checked the 4.2.2.3 +12V CPU Power Connector (Required) in Single Rail Power Supply ATX12VO Design Guide and 4.2.2.5 +12V Power Connector in Power Supply Design Guide for Desktop Platform Form Factors. Molex 39012040 and 444761112 are used on the PSU and 39299042 on the motherboard.

The maximum current can be found in the Part Details ➞ Electrical ➞ Current – Maximum per Contact on their datasheet respectively:

1. molex 39012040: 13.0A
2. molex 444761112: 11.0A
3. molex 39299042: 9.0A

Because the voltage is 12V and the minimum curent of the above parts is 9.0A, the maximum power is 12V x 9.0A = 108W. There are two power and two ground in a 4-Pin connector.

Reference

1. Intel: Single Rail Power Supply ATX12VO Design Guide
2. Intel: Power Supply Design Guide for Desktop Platform Form Factors
3. molex: 39012040
4. molex: 444761112
5. molex: 39299042

Build the Linux Kernel Module to Enable RTL8811CU/RTL8821CU USB Wireless Dongles

There is no built-in support for Realtek RTL8811CU^[1][2] and RTL8821CU^[3] in Ubuntu 20.04 LTS. The later also has a Bluetooth controller. I have to download the RTL8811CU/RTL8821CU driver source code, compile to a kernel module, add it to the kernel, and switch to the WiFi USB mode.

The following USB wireless dongle uses the RTL8811CU chipset:

1. TOTOLINK A650UA^[4]

Quick Summary

For Ubuntu 18.04 LTS and 20.04LTS, follow these steps:

$sudo apt-get update
$sudo apt-get install dkms git
$git clone https://github.com/brektrou/rtl8821CU.git
$cd ~/rtl8821CU
$sudo ./dkms-install.sh
$sudo /usr/sbin/usb_modeswitch -KW -v 0bda -p 1a2b

If the usb_modeswitch doesn’t work, check the vendor and product id:

$sudo modprobe 8821cu
$lsusb

If it works, make it work automatically:

$sudo vi /lib/udev/rules.d/40-usb_modeswitch.rules
/1a2b
# D-Link DWA-171 Wifi Dongle
#ATTR{idVendor}=="0bda", ATTR{idProduct}=="1a2b", RUN+="usb_modeswitch '/%k'"

# TOTOLINK A500UA
ATTR{idVendor}=="0bda", ATTR{idProduct}=="1a2b", RUN+="/usr/sbin/usb_modeswitch -K -v 0bda -p 1a2b"

For RTL8821CU, run systemctl start bluetooth.service to enable Bluetooth.

Build the Linux Kernel Module to Enable RTL8192EU USB Wireless Dongles

The built-in support for Realtek RTL8192EU^[1][2] in Ubuntu 20.04 LTS has some issues with D-Link DWA-131 E1^[3]. It provides a weak signal and slow WiFi. To improve, I have to download the RTL8192EU driver source code, compile to a kernel module, add it to the kernel, remove the existing drivers, and fix the detection issue.

The following USB wireless dongle uses the RTL8192EU chipset:

1. D-Link DWA-131 E1

Quick Summary

For Ubuntu 18.04 LTS and 20.04LTS, follow these steps:

$sudo apt-get update
$sudo apt-get install dkms git
$git clone https://github.com/Mange/rtl8192eu-linux-driver
$cd ~/rtl8192eu-linux-driver
$sudo rmmod 8192eu
$sudo rmmod rtl8xxxu
$sudo dkms remove rtl8192eu/1.0 --all
$sudo dkms add .
$sudo dkms install rtl8192eu/1.0
$sudo depmod -a
$echo "blacklist rtl8xxxu" | sudo tee /etc/modprobe.d/rtl8xxxu.conf
$echo -e "8192eu\n\nloop" | sudo tee /etc/modules
$echo "options 8192eu rtw_power_mgnt=0 rtw_enusbss=0" | sudo tee /etc/modprobe.d/8192eu.conf
$sudo update-grub
$sudo update-initramfs -u;
$sudo shutdown -r now

Moving to Ryzen 3 2200G and Improve Jonsbo C2’s Airflow

Because of the Microarchitectural Data Sampling (MDS)^[1] vulnerabilities in 2018, computers have a huge performance impact after mitigation. Apple suggests disabling hyper-threading (HT) for full mitigation.^[2] My i3-370 (ThinkPad T410i), i5-6200u (ThinkPad L460), and i5-3210M (Mac Mini Late 2012) are all using HT. Maybe that’s why they slowdown considerably since 2019.

On the other hand, J3455 is a quad-core processor. It’s more responsive than the dual-core and the dual-core-quad-thread processors. I decided to build the next primary desktop with an AMD quad-core processor without simultaneous multithreading (SMT)^[3].

1. Computer Parts
2. Implementation
3. Temperature and Power Consumption
4. Concerns

Upgrade J3455B-ITX’s 5×5 CPU Fan to a 12×12 Intake Fan

In my previous post^[1], a 5×5 CPU fan solve the heating issue. When I restore the HDD frame, it blocks the CPU fan to pull enough cold air through the roof vent holes aka ventilation holes.

Geeek A1 Mini-ITX case^[2] has room for 4 5x5cm case fans and a 9x9cm CPU fan. Sound like a perfect solution. But after watching YouTube videos from TastyPC (7:02, 7:37)^[3], Tech By Matt (1:26)^[4], and Cevin T.^[5], I decided to customize the case and upgrade to a more powerful case fan. It’s more fun.

1. Improve Wind Tunnel for the CPU Heatsink
2. Upgrade to a 12×12 Roof Fan

Build the Linux Kernel Module to Enable RTL8812AU USB Wireless Dongles

There is no built-in support for Realtek RTL8812AU^[1][2] in Linux. To enable, I have to download the RTL8122AU driver source code, compile to a kernel module, and add to the kernel.

Following USB wireless dongles use the RTL8812AU chipset:

1. D-Link DWA-171 A1^[3]
2. Edimax EW-7811UTC^[4]
3. netis WF2190^[5]
4. TP-Link Archer T2U Ver 3.0 (RTL8811AU)

Quick Summary

For Ubuntu 18.04 LTS and 20.04LTS, follow these steps:

$sudo apt-get update
$sudo apt-get install dkms git
$git clone https://github.com/aircrack-ng/rtl8812au.git
$cd ~/rtl8812au
$sudo make dkms_install
$sudo modprobe 88XXau

 
	

Moving Celeron G3900 to the Smallest Micro-ATX Case: Jonsbo C2

The computer case for my Celeron G3900 has 4 fans. Air circulation is great but it is too big to fit on the table. I want to move it to a smaller case and keep cool.

1. Background Information
2. Requirement
3. Evaluation
4. Decision
5. Special Topics

Jonsbo C2 is smaller than some Mini-ITX cases but accepts a Micro-ATX motherboard.

Add a Fan to Resolve J3455B-ITX’s Heating Issue

My J3455 computer is quiet but runs hot in the tiny Mini-ITX case^[1]. I decided to use a fan to improve air circulation to cool.

The case is about the size of the Mini-ITX motherboard.