ASUS P5E3 Premium X48 Motherboard Review

3oh6 · | June 10, 2008

Voltage Regulation

The Voltage Regulation section is where we examine the voltages being supplied by the motherboard, how close they are to what we select, and if there is anything unusual about the voltage regulation on the motherboard. Today we will be taking a quick look at the vCORE, vDIMM, and vNB regulation. As we are well aware of at this point, the P5E3-Premium does not have a lot of voltage readings for the BIOS so there will be even fewer readings in Windows. That is why we will be looking at only the three components, because we have found accurate voltage read points. Here are the read points that we will be using. Ground for all read points was the ground pin on a fan header at the bottom edge of the board.

The leads on the underside of the motherboard that come from capacitors and inductors are usually very close to what is being supplied to a specific component on the motherboard. The first image is of the vCORE read point where we measured from both the inductor and the capacitor. The capacitor reading was always 0.002v less than the inductor and the lower value was used. The circled capacitor lead was used for measuring the voltage for the north bridge in the second photo. In the last photo, we show the pin that is read from for vDIMM voltage readings. As it turns out, there are a few surface mount capacitors in-between the DIMM slots that provide a completely accurate reading of vDIMM as well. Let's now take a look at the voltage chart and what this motherboard supplies versus what is selected in the BIOS.

	BIOS Set	BIOS Report	PC Probe II Idle	PC Probe II Load	DMM Idle	DMM Load
vCORE (Auto)	1.36875v	1.328v	1.33v	1.31v	1.332v	1.312v
vCORE (Normal)	1.36875v	1.328v	1.33v	1.31v	1.332v	1.312v
vCORE (Perf.)	1.325v	1.312v	1.30v	1.31v	1.304v	1.304v
vDIMM	1.96v	x	x	x	1.996v	1.987v
vNB	1.51v	x	x	x	1.530v	1.530v

The distinct lack of voltages being reported on is testament to how little the P5E3-Premium offers in response to the question, what is the voltage? We are provided with nothing more than a vCORE reading in the BIOS to go along with the CPU temperature and random motherboard sensor reading. No vNB, no vDIMM, no other voltages or temperatures are made available to users and that just doesn't seem right. When providing users the ability to adjust voltages to the ranges offered with this motherboard, providing BIOS voltage readings is an almost must. If for nothing more than another safety precaution, BIOS voltage readings as well as NB and SB temperature sensors.

On the recently reviewed Rampage Formula, every voltage and temperature reading you could think of was reported in the BIOS and therefore picked up in Windows by software. That is the ASUS flagship DDR2 board, and this is supposed to be the flagship DDR3 board for the X48 chipset...so why the lack of info? Either way, the voltages we were able to measure appear to be very close to what is being set in the BIOS. vCORE does drop a little from what is set but the differences are predictable and working with or without the Performance mode for vCORE is very easy. The rest of the voltages we measured were pretty close to bang on and vDIMM supplied slightly more than selected throughout the voltage range. This is no surprise but the difference is very small so we would consider it to be accurate. Here now are the vCORE charts for both Normal, and Performance, options for Load-Line Calibration.

vCORE w/Load-Line Calibration - Normal

vCORE w/Load-Line Calibration - Performance

The difference between Load-Line Calibration on Normal and Performance is pretty obvious in the two charts above. As advertised, Performance completely eliminates any voltage drooping under load. It actually flirted with a slight increase in voltage when the system was put under load. With Load-Line Calibration disabled, the standard droop for a dual core processor is evident but repeatable and predictable which makes it very manageable. There is some debate on whether vDROOP is a good thing, bad thing, or makes no difference in the life of the processor. That is not being debated here, we simply want to show the effects of this option as it is always asked in motherboard discussions.