TechPowerUp found photos and benchmark results of the ATI Radeon HD 5750 at an Asian tech site. This mainstream card is expected to be available within a couple of weeks.
Here's the interesting part, the performance figures unearthed by the previewer. The HD 5750 was pitted against Radeon HD 4850, HD 4770, and GeForce GTS 250. At 3DMark Vantage (GPU score) and 3DMark06, the Radeon HD 5850 outperformed both the Radeons from the previous generations, and edged past the GeForce GTS 250, which were tested on the same testbed. After 220 seconds of FurMark, the Radeon 5750 was chugging along at 70 °C, with an average frame-rate of 35 fps.