Yes, a high-end CPU typically requires VRM cooling to maintain stable performance.
Yes, a high-end CPU typically requires VRM cooling to maintain stable performance.
You're checking if the ASUS B85M-E/CSM motherboard can support a 4790 CPU. The VRM appears less effective, and you're concerned about the lack of cooling for such a high-power chip. It's worth considering whether the benefits outweigh the risks, especially with the cooling concerns.
It's not the most efficient choice, but Haswell CPUs consume very little power. Their built-in voltage regulator reduces the VRM's workload, making it easier for the board to function properly. Running the chip at standard settings should work fine. However, Haswell components have been less appealing for several years—why are you considering this board?
I have a friend who doesn’t have the money to purchase or assemble a computer, so I decided to gather some components and create a functional one for him. I already have a case with a 500-watt PSU, an 1050Ti GPU, 16 GB DDR3 RAM, and I just need a motherboard and CPU.
Fair point, but I’d still suggest checking other components. Older AM4 parts tend to be more affordable compared to Haswell CPUs like the 4790, yet they offer significantly better performance. You’d need to replace your RAM setup, but 16GB of DDR4 can be found for around $20 if you purchase used, which should keep the overall cost similar for a quicker system.
Haswell includes an on-chip voltage regulator and doesn't need a strong VRM. That should work, but it's not sufficient for OC. Keeping some airflow in the VRM region is always beneficial, though... Active cooling isn't necessary.
It's a B85 chipset, overclocking is limited. The processors don't consume a lot of power... but even if they do, the motherboard can have a bios which monitors the temperature of the VRM and if the temperature goes too high, it can temporarily tell the CPU it can only supply some amount of power until it cools down a bit. For example, a 4790 may consume 60-80w normally and may peak to 100w when using all cores (like for example rendering a video using cpu only) and it may take 15-20 minutes for the VRM producing 100w to heat up to the maximum temperature at which point the bios will tell the cpu "i need to throttle you down to 80w to have some time to cool down". How fast a VRM heats up depends on the efficiency of the mosfets / power stages (those square chips between the capacitors and the inductors, the square things with R68 written on them) and how well they cooling system is implemented - if the mosfets are cheap then they may be less efficient and need more cooling. On this board, there's enough space between the mosfets that I suspect the designer relies on purpose on the copper in the motherboard layers to work as a heatsink and they're also assuming this motherboard will be used in office computers or systems where a cooler blowing air down into the cooler and therefore blowing air down onto the motherboard will be used, so the air from the cooler will also help cool down the motherboard.
They’re generally low power usage and come with built-in voltage regulators, which is something I wasn’t aware of. I found a board similar to the Asus B85M running the 4460 and it’s been working well. But without knowing the board’s background, it might have been poorly built—maybe a tight case, poor ventilation, and possibly a failing GPU. I’d prefer a more durable option to ensure better performance and value. If you decide on one without VRM heatsinks, consider using a cooler with strong airflow, such as the standard ones. Also, I often see older Ryzen boards sold with AM4 chips for around $70–80; that would be a smarter choice.