VRM Cooling fans
VRM Cooling fans
Asus recommend choosing either a 40 mm or 50 mm fan for local cooling, near the VRM, to help with overclocking. Some users have tried this and wanted to know if it really matters. There are also suppliers in the UK who can provide these fans. Thanks.
You can ignite a stick of incense and place it near the VRMs to assess air movement. Fans don't expel air directly from the back; instead, they disperse it in a wide, shallow cone shape. Silverstone produces some AP "air penatrator" fans that propel air over longer distances.
The standard coolers we've relied on for years deliver airflow not only to the CPU but also to the entire socket area. This enables some cooling around the VRMs. Tower coolers used today for superior CPU cooling don't provide any airflow to the socket, and the VRMs can experience issues due to the absence of movement. I was part of a discussion about an OC issue a few weeks ago where someone noticed high temperatures in a program. After assisting them, it turned out the problem was with the VRMs. Someone connected an old 40mm fan to the sinks, achieving a nearly 20°C reduction on the VRMs and stabilizing the OC as well. It really does matter. You can purchase specialized fans or simply use an old 40mm fan and secure it properly—using zip ties or tightening screws if the fins are sufficient.
The worst scenario for VRM airflow is a water loop that blocks all airflow from the VRM region completely. VRM cooling can deliver higher and more consistent voltage during overclocking. It's quite simple to revert to a less effective setup. This aspect is equally crucial as CPU cooling.
The standard coolers we've relied on for a long time offer airflow not only to the CPU but also to the entire socket area. This enables some cooling around the VRMs. Tower coolers used today for better CPU cooling do not provide any airflow to the socket, and the VRMs can experience issues due to the lack of movement. I once saw someone with a failed upgrade notice a high temperature in a program. After assisting them, it turned out the problem was the VRMs. They connected an old 40mm fan to the sinks, achieving a nearly 20°C reduction on the VRMs and stabilizing the OC as well. It really does matter. You can purchase dedicated fans or even repurpose an old 40mm fan with zip ties or a screw if needed. I'm currently using a 240mm top-mounted liquid cooler, so the intake of one of those fans is about 2 inches from the VRM, prompting me to consider if another small fan would help. Plus, local suppliers in the UK don't seem to stock anything smaller than 80mm.
It significantly impacts the temperatures of my mobile northbrige, enabling stable temps below 65°C (instead of 75–80°C without VRM fan), keeping the system responsive during games.
There are many 60x15mm and 50x15mm 3pin fans, some blower-style small fans available on eBay, though they spin faster and are noisier (requires a low-noise adapter with resistors like Noctua, rated up to 100 Ohm) or a Molex to multiple 3pin fan adapters with 5V output, but the lower RPM may reduce cooling efficiency.
Mounting the fan can be difficult; the best options are older memory coolers with plastic legs and mounting clips, sometimes using mono or dual fans, though they often need connector adjustments for 3pin setup and RPM control (can be loud).
Some older motherboards, like Asus small vertical fans, may require extra work to install.
I’ve used a Gskill memory fan on the Crosshair formula V north bridge in vertical position with metal legs, fitting it perfectly onto VRM edges. I modified it into a 3pin fit for the board and controlled speed via the motherboard, achieving good results. Now I’m using drive cage 2x120mm fans, which offer better performance and more precise speed control.
It's interesting to note that my setup includes a 360 AIO at the top blowing air out and two 200mm fans at the front pushing air in. I recently purchased the H500p Mesh, but the rear 140mm fan is directing air into the CPU and VRM area. This significantly impacts the VRM temperatures, especially since I only have a waterblock over the CPU and no active cooling. The rear fan now blows air over the VRM components before it exits through the top via the 360 AIO. Overall, I’m seeing much better temperatures now—just a suggestion to consider.
It has a clear impact on the temperatures of my mobo northbrige, letting me keep temps below 65°C (instead of 75 to 80 without VRM fan), and the system feels more responsive while gaming.
There are many 60x15mm and 50x15mm 3pin fans, along with some blower-style small fans on eBay; they spin faster and are noisier. I need a low-noise adapter with resistors like Noctua (with multiple resistors up to 100 Ohm) or a Molex to multiple 3pin fan adapter with 5V output, though the lower RPM might not provide good cooling efficiency.
Mounting the fan can be tricky, so the best options are old-school memory coolers with plastic legs and sometimes mounting clips or mono/dual fans, though they often require some work with connectors to adjust RPM (which can be loud).
Some older motherboards, like Asus small vertical fans, may need extra effort to install.
I’ve used a Gskill memory fan on Crosshair formula V north bridge for years in vertical position with metal legs covered by an electric fitting that fits perfectly onto VRM edges. I modified it into a 3pin fitting for the mobo and controlled speed through the board, achieving good results. Now I’m using drive cage 2x120mm fans, which give better control over fan speeds.
I found that Noctua has a 24V 40 mm 4-wire PWM fan. It does sound a bit different when plugged in, but you’ll need to change the plug to connect it to a mobo fan header. Asus provides a download for making a mounting bracket with a 3D printer (I wish I had one). Vmax’s suggestion to reverse the fan sounds reasonable; fitting a small air scoop could help redirect airflow. A slight positive air pressure might be useful, but adding a filter at the intake would also be a good idea.
Malcolmf shared some insights on cooling options for his system. It helps noticeably lower temperatures in his Northbrige motherboard, keeping it below 65°C instead of 75–80°C without a VRM fan, which keeps performance smooth during games. He mentions many 60x15mm and 50x15mm 3pin fans are available, some blower-style small fans on eBay, though they spin faster and are noisier. He suggests low-noise adapters with resistors like Noctua (capable of up to 100 Ohm) or a Molex adapter with multiple 3pin fans and 5V output, but notes that lower RPM might reduce cooling efficiency. Mounting the fan can be tricky; he recommends older memory coolers with plastic legs or mounting clips, sometimes needing connector adjustments for 3pin compatibility and speed control (which can be loud). He also points out some old Asus small vertical fans may require extra work to install. He shares his experience using a Gskill memory fan on the Crosshair formula VRM north bridge in vertical position with metal legs, modifying it into a 3pin fit for the motherboard and controlling speed via the board. He switched to drive cage 2x120mm fans for better results and control. He found a Noctua 24V 40mm 4-wire PWM fan useful, though changing the plug is needed for VRM headers. Asus provides a downloadable mounting bracket using a 3D printer (though he wishes he had one). Vmax’s idea of reversing fan sounds reasonable; adding a small air scoop could help redirect airflow. A slight positive pressure might be beneficial, but installing a filter at the intake would also be wise.
40mm fans in the UK... Novatech offers some options: https://www.novatech.co.uk/products/comp...s/40-70mm/ Overclocker has a selection here: https://www.overclockers.co.uk/air-cooli...mm-pc-fans Hope this assists...