Radeon HD 3830 (previously called Radeon HD 3690) is a high-end GPU based on the 55nm, second unified shader architecture, R600.
It's based on the RV670 PRO Core and offers 320 Shader Processing Units, 16 TMUs and 16 ROPs a 128-bit memory interface of standard GDDR3. The central unit runs at 670MHz and the memory clock runs at up to 830MHz.
It can be addressed as a Radeon HD 3850 with half the memory bandwidth.
Under most circumstances, Radeon HD 3830 is expected to offer exactly the same performance as Radeon HD 3850. DirectX 11 games aren't supported.