MSI 790FX-GD70 AM3 Motherboard Review

Voltage Regulation

Most people don’t realize that stable system power is the responsibility of more than just the PSU. A motherboard is essentially a complex power supply on its own, converting 12V and other supplied voltages to the required outputs for various system components. We’ll be validating the GD70’s “dialed in” voltages in the BIOS using a digital multimeter.


MSI was kind enough to label many voltage read points across the GD70. Unfortunately, quite a few of them are obstructed by the heatpipe cooling solution. None the less, it certainly takes the guess work out of the process. For our tests today, we’ll be measuring three of the most critical system voltages; CPU core voltage, CPU-NB voltage and memory voltage. For grounding purposes, we used the ground lead on a fan header toward the bottom of the motherboard.


As you can see the GD70 does very well when it comes to voltage set accuracy. For the most part, specified values in the BIOS are within 0.025V in actuality. The vCORE tends to undervolt very slightly and does droop by about 0.01V under load, but that is about the extent of it. The CPU-NB tends to overvolt a little more than we’d like to see. A value of 1.40V set in the BIOS equated to 1.447V in actuality. In our opinion, a 0.05V variation is a bit too much and overclockers will need to cognizant of this. DIMM voltage on the other hand is extremely accurate. Every single step up was right on the money with only 0.007V of deviation.

All of the voltage outputs were extremely stable and steady when being examined on the DMM. Overall, we were very pleased with what we saw.


Thermal Performance

To test the effectiveness of MSI’s heavy-duty passive cooling solution, we conducted some basic temperature measurements using a digital thermometer. Although there are two built-in temperature probes on the GD70, we were unable to determine their exact location and questioned their accuracy. We attached our probe to the heatsink on the Southbridge as well as the main heatsink close to the MOSFETS and farther down toward the 790FX.

Full system load was achieved using Prime95 “Large FFT” testing while “Furmark” was run to get the GPU all toasty. For the best effect, we wanted to measure temperatures in a less than ideal cooling environment. To accomplish this, we disconnected our Tech-Station side fan, and let the motherboard heatsinks run entirely passively. Our Noctua NH-U12P provides a small amount of collateral airflow to the MOSFET/790FX heatsink, but very little in comparison to a case with good circulation.


As you can see the heatsinks can get quite toasty, but contrary to popular belief, this is actually a very good thing. This means that a great deal of heat load is being transferred up from the components to the base of the heatsink. We were also very pleased to see that actively cooling only the upper portion of the heatsink resulted in a quick reduction in Southbridge temperatures. Clearly the heatpipe joining the two heatsinks is very functional and not just a cosmetic addition to the board.


Power Consumption

Since its not every day that we run into a motherboard with active phase switching, we thought we should conduct some power consumption tests. Full system power consumption – minus the monitor – was measured using a UPM EM100 power meter. Full system load was achieved using Prime95 “Large FFT” testing.

Tests were conducted with AMD’s Cool’n’Quiet enabled and disabled, and then repeated with “GreenPower” phase switching set to “Auto” in the BIOS.


Although it’s not terribly significant, we were consistently able to see a savings of about 3W with “GreenPower” enabled. With the system at idle, both the memory and CPU phases were chopped down to a single phase. As soon as significant load was put on the processor and memory, the phases would jump back up to their default values. Since the system needs full-phase power at load, there were no improvements realized in any of the configurations.

We were pleased to see that GreenPower worked seamlessly and caused no amount of system instability.