Today, Asus has claimed that is has perfected the Radeon HD 4890 and the RV790 GPU, with a custom-designed videocard that it calls the EAH4890 TOP. The EAH4890 TOP has everything you'd expect from a reference Radeon HD 4890: the GPU and shaders are clocked at 850MHz and accompanied by 1GB of GDDR5 memory that runs at an effective speed of 3.9GHz (975MHz quad-pumped). Where the Asus EAH4890 TOP differs is in its construction. Asus has made dramatic changes from AMD's reference Radeon HD 4890, with a re-designed PCB, new power management, an improved heatsink, and more powerful air cooling. The result is a videocard that holds a lot of promise for some extreme overclocking and tweaking.