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Low quality MB with VRM

Does entry level motherboard, which comes with VRM (B450m S2H), causes CPU heat up more quickly and less clock boosting overhead?

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a low quality board simply can't supply the needed power for say a 3700X meaning the CPU will likely stay at base clock or below it.

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12 minutes ago, Rumman said:

Does entry level motherboard, which comes with VRM (B450m S2H), causes CPU heat up more quickly and less clock boosting overhead?

It doesn't cause the CPU to heat more and the less clock boosting overhead is debatable.

 

The VRM (the circuit which converts 12v to the voltage the processor needs) can function up to a certain temperature, let's say 100 degrees Celsius.

Depending on how much power the processor consumes, this circuit will heat up more (because of losses due to efficiency).

If the processor overall doesn't consume a lot of power (which is the case for most 4 core cpus and some 6 core processors if you don't overclock them), this power consumption is low enough that the VRM doesn't reach that peak temperature ever.

With more power hungry processors, that peak temperature can occasionally be reached.

 

A processor doesn't consume a constant amount of power all the time, like for example a light bulb. 

The processor automatically adjusts the frequency of each core as needed - if you have an application or game that uses mostly two cores, the processor will reduce the frequency of the other cores or even turn them off for short periods of time to save power.

 

So let's say you have a quad core processor like Ryzen 2200g or Ryzen 1400 which consumes around 40 watts at maximum 100% on all cores, but only 10-20 watts when idle (when you're watching movies, typing a comment on this forum and so on)

 

When idle, the VRM will slowly go up from around 25-30 degrees Celsius ambient temperature and will slowly go up to let's say 40-50 degrees Celsius and stay around that temperature (the heat is dissipated into the motherboard and is moved away by the cpu fan and other fans in your case)

When you start a game or some application that uses a lot of cpu power, your processor starts to consume 40 watts or so, and now the VRM starts to produce more heat.  So, it will gradually go up in temperature and will probably stay at around 60-70 degrees.

A heatsink on the VRM will slow that gradual rise in temperature and will keep the temperature lower.

So for example, let's say with a quad core, it will take one minute for the VRM to reach 60-70 degrees in temperature and stabilize there. With a heatsink on the VRM, it may take up to 5-10 minutes to reach around 55-60 degrees Celsius.

 

Either way, the temperatures are well below that threshold of 90-100 degrees Celsius.

 

Now, let's repeat with an 8 core processor that consumes 100 watts when all cores are at 100%

 

When idle, same story, the cpu doesn't consume much.

When load, the temperature starts to rise up, and probably within a minute, you may reach 85-90 degrees Celsius.  With a heatsink on the VRM, it may take 5-10 minutes to reach 90-100 degrees or the heatsink may actually be good enough to always keep the VRM below 90 degrees.

If the temperature goes above 90 degrees, the BIOS and the vrm controller detects that and sends a signal to the cpu : "Hey CPU, try to reduce your power consumption and give me a bit of time to cool down because I'm too hot"

So, now your CPU will throttle, it will reduce the frequency of some cores and will turbo boost less often or not at all in order to consume less power.

As the cpu demands less power, the VRM produces less heat, so it will gradually cool down... it may take a couple of minutes to go from 90 degrees Celsius to let's say 70 degrees Celsius.

At some point where the temperature is low enough, the bios or vrm controller may tell the CPU "ok, you can go nuts again and boost and go 100%, I'm cool enough"

 

With no heatsink or minimal heatsink, you'll soon notice kind of like a seesaw effect where the temperature of the vrm goes up and down a few degrees. If you're doing something heavy that keeps the cpu at 100%, you'll however notice that after some period, once that vrm high temperature is reached, the cpu will more or less stay with a bit of throttling, because the vrm heats up faster than it cools down, so it never gets a chance to cool down and stay below that temperature threshold.

So, the cpu will always throttle a bit, which means it will actually consume less power and therefore should actually be a bit cooler.

 

 

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