Gigabyte GA-EP45-UD3R & abnormal voltages


Dec 19, 2008
Hello all,

I recently built a new machine and have a concern about the motherboard I've purchased. I've read a lot of positive reviews about the EP45-UD3R, so I decided to give it a shot. Everything is functional on the board and it overclocks like a champ, but the 12v rail and vCore are off by a considerable amount. Before I explain, here is the core of my build:

Intel E5200
G.Skill PC2-6400 Pi Black
Sapphire Radeon HD 3870 GDDR4
PC Power and Cooling S61EPS 610W

As you can see, the components I bought are fairly low end and shouldn't stress the PSU at all, but I'm still getting weird voltage reports. Here are a couple of scenarios I've run through while trying to figure it out:

Scenario 1

CPU @ 2.5 (stock)
FSB @ 200 MHz (stock)
Line-Load Calibration ON

vCore BIOS setting @ 1.225v (stock)
vCore BIOS report @ 1.201v
vCore Windows report IDLE @ 1.180v
vCore Windows report LOAD @ 1.160v to 1.180v

12v rail BIOS report @ 11.795v
12v rail Windows report IDLE @ 11.795v
12v rail Windows report LOAD @ 11.795v
12v rail DMM report IDLE @12.11v
12v rail DMM report LOAD @12.11v

Scenario 2

CPU @ 3.663
FSB @ 333 MHz
Line-Load Calibration ON

vCore BIOS setting @ 1.400v
vCore BIOS report @ 1.360v
vCore Windows report IDLE @ 1.344v
vCore Windows report LOAD @ 1.312v to 1.344v

12v rail BIOS report @ 11.795v
12v rail Windows report IDLE @ 11.795v
12v rail Windows report LOAD @ 11.795v
12v rail DMM report IDLE @12.11v
12v rail DMM report LOAD @12.11v

As you can see, BIOS is reporting my 12v rail as being undervolted by 0.3125 volts where the DMM used is showing a solid 12.11 under all conditions. That would be fine and dandy, but the vCore is undervolted as well AND there is a swing of -0.088 to -0.056 while overclocked with LLC turned on. This seems like a bit much to me and it DOES affect stability when overclocked. Just for giggles, I tried an Antec Basiq 500w and found the voltages to be slightly worse off.

At this point I'm pretty sure its the motherboard, but I need to know the following:

A) Is anyone with this board is encountering the same problems as me?
B) Is this acceptable varience for this setup?
C) Do I have a board with defective VRM components?

Sorry for the verbose post, but I want to be as clear as possible. I've got 14 days left for a RMA and need to get this sorted out ASAP.


Dec 23, 2008
Those 12V are well within tolerances, completely normal.

Your vCore, I guess you are leaving voltage on "Auto"?

Are you running DES? If not, then the voltage is probably just being adjusted by the standard C1E/C2E etc. which you can turn off, but they do save a fair bit of power.

I have the GA-EP45-UD3P board with a E6300 cpu, which is 1.3v, 266FSB, x7@1.86Ghz stock.

I run with DES on, if I push my FSB up, then "Auto" voltage gets set at 1.4V past about 300Mhz, and I see exactly the same actual voltages as you (when at 333 or anything really).

But what I have done is set the voltage manually to 1.3V and run the FSB @ 376Mhz. DES kicks in and it uses 1.104V idle up to 1.232V (!!) full load. Power consumption is incredible.

If you really want to reach the absolute maximum overclock then most people disable all power saving features, but for reasonable overclocks then they should still work stably.

There are a lot of features and options on a board like this, but that's a good thing, just takes a bit of time with it.