Voltage Regulation

To take a look at a board’s voltage regulation, we first need to know a few voltages. More specifically vcore - BIOS set vcore, vcore in windows, and vcore under load. In theory these numbers should all be the same but load line droop (commonly known as Vdroop) is an intentional part of any Intel power delivery design specification.

Droop by definition is the real voltage delta from idle to load on a motherboard. Vdroop is usually larger for quads due to the extra power going through the voltage regulation integrated circuits and some boards have larger vdroop than others, depending partly on the quality of the voltage regulation of the board.

What we will look at on the Penryn1600SLIX3-Wifi is vdroop and how smooth the voltage line on an overclocked system is over a 5 hour period. For these tests OCCT monitoring is used and the readings are confirmed to be VERY close when measured with a digital multimeter.


Voltage set in the BIOS for the Xeon chip is 1.38v, giving 1.35v idle and 1.30v load. Taking this into perspective it isn’t too bad; ideally we like to see .02-.03v droop from idle to load and the Penryn1600SLIX3-Wifi only gives .05v droop on a 45nm chip. However, the more power used by the processor, the harder the motherboard voltage regulation ICs must work and the more heat is produced. We see this example illustrated with the quad tests.

The Q6600 voltage set in the BIOS is 1.41v, giving 1.33v idle and 1.25v load. Vdroop in this case is .08v and this figure increases as voltage goes up. Also concerning is the amount of actual voltage that is utilized under load compared to what the user may expect from a BIOS setting. Considering this board has a maximum of 1.6v available in the BIOS, users shouldn’t expect much over 1.4v load with a 65nm quad. ASRock likely restricted vcore to 1.6v so users would not use more voltage than the voltage regulation transistors and ICs can handle safely.

Looking at CPU power consumption, almost a 30W increase in power usage is noted, about a 35% increase. These figures are recorded under load conditions and were measured using the Sandra Processor Arithmetic Benchmark.



Heat Analysis

The Northbridge on the ASRock Penryn1600SLIX3-Wifi is runs exceptionally hot, even with heatpipe cooling. When a heatsink is so hot to the touch it almost burns at stock speed and voltage, that is an unusual occurrence. Measuring the Northbridge heatsink with a digital thermometer temperatures hover around 57-58C, which means the actual chipset is even a few degrees hotter than that. Changing Northbridge voltage to high and applying the overclock tested in the overclocking section, the temperature rises to almost 80C! For comparison, most boards don’t see much over 50C even at high Northbridge voltages. These unusually high temperatures could mean there is insufficient NB cooling for the amount of heat produced and this could also be a contributing factor to below average FSB clocking.