Mainboard efficiency and energy usage.
Mainboard efficiency and energy usage.
Hello, I understand the situation. People seem indifferent, but I'm assembling a camper and prefer a regular desktop with an 8700G APU. The alternative is a laptop, though I need flexibility since I can swap components later. For example, if something fails in Spain, I just need to purchase a specific part instead of replacing the whole device. How does the chipset or VRM affect power consumption on a mainboard? I assume a B650 uses less power than an X670. But what about the VRMs—would option a draw more power? a) vcore 5x 55A NCP302155 with two 55A NCP302155 (plus 2 PWM without doublers, Gigabyte B650I AX) b) vcore 8x 50A SiC654 with two 50A SiC654 (4+2 PWM with doublers, AsRock B650M-HDV/M.2) c) vcore 8x 105A RAA220105 with two 60A NCP303160 (plus 2 PWM without doublers, Gigabyte B650I Aorus Ultra). I believe more phases provide a steadier voltage, and my research also suggests that faster PWM switching is less efficient. Any insights would be greatly appreciated. I don’t need to know which model is fastest, just general advice.
In theory it's yes, but AMD boards typically come with minimal LLC by default, so the variations aren't significant. Not dramatically so, though. Most boards run at around 500kHz and can't be adjusted, making it essentially a minor point. Answering this question from just a spec sheet is tricky. While you can get an approximate load estimate, the efficiency figures differ across brands due to varying power stages and test methods. The VRMs also change their setup, affecting performance at low loads. To assess efficiency accurately, check the part number for detailed curves or look up the manufacturer's data. For the B650I AX, start by estimating current draw (assuming a 65W limit, roughly 60A), divide it by the number of power stages (about 5), resulting in ~12A per stage. Review the efficiency chart to see losses at typical input and output voltages. In practice, the B650I AX tends to be less efficient than others, and even it may lose a bit with VRM losses. Saving a few watts on other boards could help, but overall power draw under full load usually doesn't be a big concern. Idle consumption is likely negligible compared to the rest of the system. The main factor affecting efficiency often comes from how the motherboard handles low-power phases, which isn't easily known without testing the boards directly.
It depends on the load you're applying to the VRM. At low loads they tend to be less efficient, but overall power usage isn't high. Efficiency improves with higher power until a certain threshold, after which it declines again. Adding more phases generally boosts efficiency compared to fewer phases with identical parts.
What I want to emphasize is that these factors usually have minimal impact. You might save a few watts by fine-tuning the setup. If power consumption matters, consider a mini-PC—it can help avoid damaging a laptop. Motherboard components aren't built for extreme efficiency like those in laptops. With a mini-PC you'll likely get better power optimization. The processor itself can't be replaced, but a failing CPU is unlikely, making it a reasonable trade-off.
I see, the power gap is minimal. I expected around 5-7W, but with a 5kWh battery, 7W running for 9 hours equals 63W. Thanks a lot... I should create another thread.
I suggest checking numerous reviews with detailed power ratings, as it’s often difficult to gauge performance otherwise. Sometimes, the manufacturer’s BIOS setup plays a bigger role than the hardware itself, adding 3-4 watts just by default. For building an efficient desktop at lower power levels—something laptops aren’t designed for—I recommend doing your own research and testing. Mini PCs with similar graphics to desktop CPUs (like 760M or 780M) are a good choice because they tend to have accurate power usage data and better optimization. I understand your worries about upgradability, but keep in mind that APUs have a more consistent power range compared to GPUs, which can vary widely depending on the workload.
It can offer several advantages: more features mean additional ICs, which leads to increased idle or office usage power consumption. A lower-end VRM results in reduced efficiency (*) but this depends on heavy CPU load. For office tasks, YouTube, etc., the difference is minimal. At light loads, a larger VRM might perform worse (some designs adapt phase counts based on demand). Software plays a role too—many motherboards restrict BIOS settings that lower power draw. You don’t always need top-tier power delivery; a stable, smooth voltage works well while undervolting the CPU. Setting the power cap in BIOS is often the most effective approach.