Direct from Asus's P5E3 Premium motherboard pages:
http://www.asus.com/products.aspx?l1=3&l2=11&l3=640&l4=0&model=2069&modelmenu=1
Enables the Most Energy Efficient Motherboard in the World
Enables the Most Energy Efficient Motherboard in the World
The ASUS EPU utilizes innovative technology to digitally monitor and tune the CPU power supply with improved VR responses in heavy or light loadings. It automatically provides power for higher performance or improve efficiency by 50% when the PC is running low intensity applications. Working together with AI Gear 3+, this can help you attain the best possible power efficiency and energy savings up to 80.23% to help save the environment.
Gigabytes claims 58.6% is a more realistic energy savings figure. They also state that they test under load. So what they are really ridiculing Asus for, is performing 8.6% better than their excerpt claims for low intensity apps. They claim auto phase changing, but don't really give details. My suspicion is that they just mean changing power modes based on load like is done in various laptop components. So it makes sense that undervolting and underclocking the components would be considered. I see no mention of the "PWM phase changing" that Gigabyte is so interested in denouncing. I also see nowhere on the site that claims to use Japanese solid capacitors. As an engineer, I feel that a drop in price with no change in performance, stability, and reliability is a good thing.
So what Gigabyte really seems to be saying is:
Asus didn't do phase change the way we did. Ours is more advanced.(So they are lying)
Asus posted a statistic based on an idle system in addition to their low intensity stat. They should only post the stat that we post for comparison. (So they are lying)
Asus is making their board cheaper by using non-Japanese capacitors and didn't specifically state that they were not Japanese caps on their site. (So they are lying)
The fact of the matter is, Gigabyte has the more advanced phase change system. Gigabyte (only) posts the more realistic statistics on their site. Finally, Gigabyte uses the better capacitors.
However, from what they show, I can't say Asus lied about any of it. I don't know about previous comparisons, but it seems like Asus just tested in a way that emphasized their strengths. Gigabytes testing was obviously done in a way that emphasized theirs. Posting extra (useless?) statistics, while typical of marketing, isn't lying. If Asus deems that "Japanese" solid capacitors aren't necessary from a reliability standpoint, why should I be upset. After all, it wasn't too long ago when they were all electrolytic. Ironically, they didn't blow up on a regular basis either.
If Gigabytes methods are so much better than Asus's, then it will show in the end product. Gigabyte should try making sure good benchmarks are present to show this rather than bicker over method's and marketing.