AMD's latest Catalyst drivers override AMD's firmware settings, resulting in the Quiet and Uber modes performing pretty much the same (at least according to the results of my maddeningly-long time in the lab with these cards). The only difference I found was that the air-cooled card reached a lower idle state in Quiet mode, and I'm using that more conservative idle state in these power numbers.

The system with our air-cooled Radeon R9 290 only idles down to 102 W with the Uber firmware selected. Overclocked, the air-cooled card could have dropped to 105 W if we were using the Quiet BIOS and our more aggressive clock rate settings. Conversely, VisionTek's CryoVenom R9 290 doesn't exhibit the same behavioral difference.

The overclocked air-cooled card's higher idle temperature can be partly attributed to the fact that its power consumption doesn't drop as low with Uber mode engaged. I checked, and at the same clock rates, Quiet mode would have allowed it to drop to 22 °C over-ambient.
Overclocked, the retail card's lower temperature comes from a higher fan speed that adversely affects noise.

Less thermal throttling allows VisionTek's CryoVenom R9 290 to gain 2% performance over the air-cooled board running at the exact same frequencies. It also enjoys 6%-higher overclocked performance.

Using the stock Radeon R9 290 as a baseline, we find that the CryoVenom can improve efficiency by up to 19% under the effects of overclocking. It's even 11% more efficient than the stock card, using the same BIOS, at stock clock rates. Lower temperatures do wonders for efficiency.
- Can A Liquid-Cooled Radeon R9 290 Be Affordable?
- CryoVenom R9 290: Meet The Card
- Test Hardware And Benchmark Settings
- Overclocking
- Results: 3DMark
- Results: Tomb Raider And F1 2012
- Results: Arma 3
- Results: Battlefield 4
- Results: Far Cry 3
- Results: Metro: Last Light
- Power, Heat, And Efficiency
- Making A Value Case For Water-Cooling A GPU