Blog → Cooling the MSI GF63: real undervolting for the i5-12450H and 6 more methods

A few years ago, I switched from a PC to a laptop. I didn’t spend much time choosing and just went with the simplest MSI GF63 model, equipped with the bare-minimum acceptable RTX 4050 graphics card and the corresponding i5-12450H processor.

I then made some upgrades: a 1TB Samsung 980 Pro, 64GB RAM (greatest possible for this motherboard), and a Honeywell PTM7950 thermal interface material. Right after that, it would have been an excellent workhorse, if not for one “but” – an extremely weak cooling system with a single cooler. Under heavy load, the 12450H would instantly heat up to 95°C and start throttling.

Long story short, I managed to solve this problem without putting the laptop in the fridge, attaching a water cooling system (yes, people actually do that), or even using Peltier elements – heaven forbid. On my unit, I dropped CPU temperature by ~25°C at idle and ~20°C under load without huge performance loss.

There is no silver bullet here. It’s a complex set of methods that I will list below, including both the obvious ones and those that are less talked about. Their effectiveness varies, depending on the specific processor die, ambient temperature, and how the laptop is used. These methods should be applied in combination, but selectively and with their drawbacks in mind.

It is assumed that the laptop is used primarily in a stationary setting – some methods will reduce battery life.

Phase-change thermal interface material

The stock thermal paste is only good enough to get the laptop to turn on in the store so the buyer can see Windows booting up. There’s nothing else good to say about it, so it should be replaced immediately.

The aforementioned Honeywell PTM7950 thermal interface material does not fundamentally solve the overheating problem, but with it, the average temperature drops by a few degrees and the processor cools down much faster after peak loads. And most importantly – the PTM7950 is significantly more durable than standard thermal paste.

Cooling stands

The very first primitive solution was a cooling stand. Simply raising the laptop was obviously not enough, so I chose the IETS GT626 turbo-fan model – exactly what is proudly called the “best in class”. The laptop sits on a polyurethane foam pad, and the fan blows cool air into the perforated bottom cover under some pressure.

Does it work? Yes, the GT626 definitely lowers the temperature by 10-15°C during certain peak loads, but it doesn’t prevent sudden spikes up to 80-85°C, further temperature increases, or throttling when performing particularly demanding tasks, such as indexing a couple hundred megabytes of code. Additionally, at its maximum speed of 2800 RPM, the fan is as loud as a plane taking off.

Is this or a similar stand worth it, given the drawbacks? Yes, it is. First, at acoustically acceptable speeds up to 1200 RPM, it still lowers the temperature, albeit slightly. Second, its design includes a dust filter, and anything trapped in it won’t get into the laptop itself. Third, it has a USB hub that draws power from the mains, thereby reducing the load on the motherboard’s power circuits.

MSI Cooler Boost

Enabling Cooler Boost in MSI Center forces the Aavid N413 fan to run at ~5500 RPM. While this shortens its lifespan, the unit only costs about $10, effectively making it a consumable.

So, if you don't mind the noise (which is still much quieter than an IETS cooling pad) and are okay with replacing the fan and thermal interface every few years, you can consider picking up a spare N413 and letting the current one run for all it's worth.

Switching graphics tasks to dGPU

In this MSI laptop, the power of the RTX 4050 discrete graphics card is limited to 45 watts – even though its chip is capable of drawing all 115 watts. However, even with this reduced power, the RTX 4050 outperforms all variants of the RTX 3050, but most importantly – it generates very little heat. Under these conditions, it makes sense to shift the load from the Intel UHD graphics integrated into the processor to the RTX 4050. This is done via the NVIDIA Control Panel, under 3D Settings › Manage 3D settings.

Reducing Power Limit (PL1/PL2)

PL1 is the maximum sustained power of the processor, PL2 is the maximum short-term power of the processor. Measured in watts.

A common piece of advice found online boils down to the following: since undervolting on the 12450H is not possible (actually, it is possible – more on that later), you need to limit the CPU’s total power via ThrottleStop. In doing so, it will automatically throttle the frequency under load to avoid exceeding the limit. Depending on the specific processor die and performance requirements, limits ranging from 35/45 to 55/65 are recommended.

Yes, with low power limits, the processor will run noticeably cooler... And much slower. Therefore, it’s better to start by limiting the cores’ turbo frequencies.

Limiting frequencies

The aforementioned ThrottleStop allows you to limit the maximum frequency of P-cores (performance cores) and E-cores (energy-efficient cores). In my case, this allowed me to achieve higher performance and more stable temperatures than if I had simply set low PL1/PL2 values.

Frequencies are adjusted in the FIVR › Turbo Groups section. In the left column, you set the multiplier for the 100 MHz base bus frequency (for example, 38 = 3.8 GHz). In the right column, you set the number of active cores for which this multiplier is active. In the simplest scenario, you can enter the same multiplier everywhere and achieve a stable frequency. Right above the Turbo Groups section is the P/E cores switch.

With default settings, the i5-12450H in the MSI GF63 can briefly boost up to 4.4 GHz, but under sustained heavy load it runs at 4.1 GHz – until it starts to overheat. Limiting the P-core frequency to 3.8 GHz resulted in an impressive 17% drop in temperature during the previously mentioned code reindexing in the IDE. Task execution time increased, but within the margin of statistical error – by 2.6%. For the E-cores, I set the frequency to 2.6 GHz; this had no noticeable effect.

After limiting Turbo frequencies it makes sense to set a Power Limit, but only as a second line of defense. The idea is that under full load, the processor should almost never hit the Power Limit or do so only briefly. You can monitor PL1/PL2 activation in the main ThrottleStop window, where a red “Power” indicator will light up when the limit is reached. At a maximum frequency of 3.8 GHz, I set PL1/PL2 to 55/65 watts.

Undervolting i5-12450H using Loadline adjustment

The CPU operating voltage is usually lowered using the Core Voltage Offset setting. On the i5-12450H, this feature is disabled, but undervolting is still possible via AC/DC Loadline adjustment.

A bit of theory. When the motherboard supplies more current to the processor, the voltage drops. To compensate for this drop, the processor requests a higher voltage from the motherboard. The “additional” volts are calculated using the formula I × AC Loadline. Those who recall Ohm’s Law can already guess that AC Loadline is measured in ohms, or more precisely, in milliohms. And if you lower the AC Loadline, the supplied voltage will also decrease.

For the 12450H processor on the MSI GF63, the default AC Loadline is set to 2.40 mΩ. This is high, and it leads to excessive heating, but such rich voltage compensation allows even less-than-ideal CPU chips to operate stably. The good news is that most chips can operate at lower Loadline values – and with less heat generation.

Load-line adjustment is done via the BIOS, but you may need to enable hidden settings first. To do this, press the following key combination: Right Shift + Right Ctrl + Left Alt + F2. After that, in the Advanced tab, go to the section: Power & Performance › CPU – Power Management Control › CPU VR Settings › Core/IA VR Settings – the AC Loadline parameter is located there. In the BIOS, it’s measured in hundredths of a milliohm: to achieve a resistance of 2.00 mΩ, enter 200. The DC Loadline parameter determines the estimated power consumption, so when changing the AC Loadline, you must set the exact same value for the DC Loadline as well.

The optimal resistance depends on the specific processor unit. It’s safe to start with 2.00 mΩ or 1.80 mΩ and gradually lower it – I, for example, settled on 1.40 mΩ (140), achieving a significant drop in temperatures.

It is generally considered that adjusting the loadline is a safe method of undervolting. Potential issues include:

• If you lower the loadline too much, you may experience BSODs under load or an even more insidious problem – clock stretching, where the actual processor frequency is lower than the declared frequency. Signs of this situation in HwInfo64: Effective Clock values are significantly lower than Core Clock (should be checked at 100% CPU load), the “Yes” flag next to IA: Turbo Attenuation.
• If you lower the Loadline critically, there is a theoretical chance that the processor won’t start at all and you won’t even be able to enter the BIOS. This can be fixed by resetting the CMOS.

Too low voltage does not cause physical damage to the processor.

Finally, a few words about the battery.

As mentioned at the beginning, I’m assuming that the laptop is primarily plugged in and its battery life isn’t a concern (many of these methods will significantly reduce it).

If you really do use your laptop this way – plugged in all the time – it makes sense to extend the battery’s lifespan in general – to prevent it from degrading prematurely or failing. Lithium batteries, as we know, don’t like being kept fully charged for too long, which is why MSI lets us set a charge limit of 50-60%. For whatever reason, this option is located in the Features › System Diagnosis section of the MSI Center. In the Battery Master block, simply select the Best for Battery mode.