ATI has ten Radeon HD 5000 series graphics cards on the market today, and if you think they are going to stop there you are sadly mistaken. Today AMD is announcing the Radeon HD 5830 graphics card, which is the ‘big brother’ of the $143 Radeon HD 5770 and the ‘little brother’ of the $299 Radeon HD 5850. Priced right in the middle at $239 the Radeon HD 5830 helps bridge the performance and the price gap between what many of our readers would consider the entry level gamer graphics cards and the mainstream gamers’ card.

The Radeon HD 5830 is a derivative of the Radeon HD 5870 and is identical not only in size, but also general features. The ATI Radeon HD 5870 has 20 SIMD engines that each have 16 Thread Processors. A thread processor contains 5 stream cores, so this is how the Radeon HD 5870 has 1600 total stream processors.(…)
Source: ATI Radeon HD 5830 1GB DX11 Video Card Review – The $239 Radeon HD 5830 GDDR5 GPU – Legit Reviews