Linus Tech Tips: Exploring the effectiveness of cooling a CPU from the back side.
Linus Tech Tips - I tried Cooling a CPU from both sides
The discussion explores the unconventional idea of cooling a CPU from the back side, challenging the common belief that it is ineffective due to the layers between the CPU and the cooler. Initial tests with a fan showed a minor temperature drop of 1-2 degrees, suggesting some potential. However, the motherboard acts as an insulator, limiting heat transfer. A custom backplate and cooler were tested, but results showed only marginal improvements. The experiment highlights that while back cooling can work, it is not as effective as traditional front cooling methods. The video concludes that the effort and cost of back cooling are not justified given the minimal benefits compared to standard cooling solutions.
Key Points:
- Cooling a CPU from the back can slightly reduce temperatures by 1-2 degrees.
- The motherboard acts as an insulator, limiting the effectiveness of back cooling.
- Custom backplates and coolers offer minimal improvements over standard cooling.
- Traditional front cooling methods are more effective and practical.
- The cost and effort of back cooling are not justified by the minimal benefits.
Details:
1. 💻 CPU Cooling: Exploring New Frontiers
1.1. Current Challenges in CPU Cooling and Enthusiast Investment
1.2. Exploring New Cooling Frontiers: Backside Cooling
2. 🔧 Attempting Backside Cooling
- Backside cooling involves pointing a fan at the back of a CPU, a method previously integrated into the Anttech 3002 case with a dedicated fan mount behind the motherboard tray.
- Preliminary tests using Noctua's magnetic mount indicated a slight temperature reduction of 1-2 degrees Celsius, from 51 to approximately 49.7 degrees Celsius, highlighting potential cooling benefits.
- This method suggests that more effective cooling could be achieved with proper contact, such as mounting a cooler directly on the backside, rather than relying solely on a fan.
3. 🔍 Challenges in Mounting a Backside Cooler
- The CPU cooler on the front must remain unaffected as it performs the majority of the cooling work.
- Mounting hardware for CPUs is designed with tight tolerances to ensure even contact with the CPU's integrated heat spreader.
- Components on the back of the motherboard, including the Intel socket back plate, obstruct the mounting of a backside cooler.
- The Intel socket back plate, holding the CPU retention arm, prevents direct contact of a second cooler with the motherboard's back.
- Out-of-the-box CPU cooling parts are insufficient for mounting a backside cooler as modifications are necessary.
- The removal of the back plate necessitates the creation of a custom back plate to facilitate proper mounting of the backside cooler.
4. 🛠️ Customizing for Optimal Cooling
4.1. Designing a New Back Plate
4.2. Incorporating Insulation Layer
5. 📉 Evaluating Cooling Effectiveness
- The back of the motherboard is not a flat surface like the CPU's IHS, making direct contact difficult, which limits cooling efficiency.
- A 1 mm thermal pad is used to cushion the cooler, but it has worse thermal conductivity than thermal paste, further hindering heat transfer.
- The motherboard itself acts as an insulator, slowing the rate of heat transfer and limiting the cooling potential at the back.
- The CPU cooler on the front is significantly warmer than the back cooler, indicating more effective heat removal at the front, highlighting the importance of cooler placement.
- The base of the CPU cooler remains at 20°C, demonstrating limited cooling impact on the back.
- Additional cooling doesn't significantly improve performance due to the motherboard bottleneck, suggesting diminishing returns for added cooling at the back.
- Testing revealed that the front cooler heats up rapidly without active cooling, illustrating its higher importance compared to the back, where cooling impact is minimal.
- Removing the fan from the back cooler shows minimal temperature change, confirming limited impact and underscoring the secondary role of back cooling.
6. 🔬 Controlled Testing and Realistic Outcomes
- The environmental chamber's constant airflow masked differences in cooling solutions, highlighting the need for realistic testing environments.
- Switching to an office-like airflow scenario revealed a CPU temperature drop of 1 to 2° using a custom back plate and fan.
- Further cooling was minimal, with improvements of 1° or less when a cooler was mounted to the back.
- Stock front-mounted coolers performed better than custom back-mounted solutions, suggesting simpler, less effort-intensive options may be more effective.
