Dynamic Energy Saver
One new feature Gigabyte touts with their latest UD2 and UD3 motherboards is Dynamic Energy Saver (DES). With this feature, the motherboard can dynamically turn on and off power phases as needed depending on workload. Say for instance youíre idling at the Windows desktop. Under this environment you donít need to run all six power phases on your motherboard. To conserve power DES can turn off power phases individually; at idle the EP45-UD3P runs with just two phases. This is all accomplished thanks to an Intersil PWM controller.
Besides automatically turning power phases on and off, the PWM controller can also dynamically throttle the CPU core clock to further reduce power consumption.
To manipulate DES, Gigabyte has developed a simple GUI that depicts the number of active power phases as well as CPU voltage and throttling:
Dynamic Power Phase:
This section represents the CPU power phases on the motherboard, six total on the EP45-UD3P. Each phase is represented as an engine cylinder, with the currently active power phases running just like they would in a carís engine.
With this setting the user can undervolt the processor. Three stages are available reducing CPU core voltage from 0.052V up to 0.085V, with the third stage reducing voltage the most. The motherboard will automatically reduce core voltage as well regardless of the stage you select, so the end user doesnít have to intervene in order for dynamic voltage to kick in.
When enabled, this setting can be used to throttle the processor for maximum power savings. An On/Off switch is provided, as enabling this setting can hamper performance in some apps. In Cinebench for instance we noted a performance hit of 2% with throttling turned on, the performance impact was negligible in 3DMark Vantage (with performance preset) however.
Speaking of performance hit, itís important to note that earlier builds of DES had a greater performance impact than newer versions. In older builds the performance hit could be as high as 20% in some apps. The latest version seems to have improved things significantly, as we noted no performance drop as long as we kept the CPU throttling setting disabled, and even when it was on we only saw a hit in Cinebench and very low-res 800x600 gaming with Company of Heroes.
What kind of power savings should you expect with DES? Gigabyte thoughtfully provides a handy ďpower savingĒ meter at the top of the utility. This measures your current power savings as a result of DES being enabled. We also ran some quick benchmarks as well:
As you can see, the power savings arenít huge, generally we saw power consumption reduced by 1-6 watts thanks to DES under load, and up to 10 watts at idle. Keep in mind that power consumption savings will vary highly depending on your PSU, with more efficient 80+ certified power supplies delivering more significant power savings than less efficient PSUs.
One additional feature Gigabyte includes on DES boards is dynamic LED. With dynamic LED, Gigabyte incorporates a bank of LEDs located in the upper right portion of the motherboard. Each LED represents one of the motherboards six power phases. As a power phase is turned on, the LED lights up. The first two LEDs are green, while LEDs three and four are yellow. The final two LEDs represent max load and shine red when active.
The EP45-UD3P ships with two PCI Express 2.0 graphics slots, with full support for ATIís CrossFire multi-GPU technology.
Keep in mind that the P45 chipset doesnít support full 16-lane operation when running dual graphics cards in CrossFire. This feature is reserved exclusively for Intelís flagship X48 chipset. Instead eight PCI Express lanes are sent to each graphics slot.
Fortunately we still havenít come across a real game that really pushes the PCI Express interface enough to become a bottleneck, 3DMark is the only app that really takes advantage of the feature.