Radeon X1900, or R580, is in many ways what the R520 should have been before all the die respins. R580 uses the same memory controller found on R520, with the 512-bit internal ring bus. Externally, the chip can address 256-bits at a time. Our Radeon X1900XT came with 512MB DDR3 running at 1.45GHz, but the X1900XTX version comes with a default memory clock of 1.55GHz. As anticipated, the R580 core features 16 pixel pipelines with 48 pixel shader processors. R580 is produced on a 90nm process. Unfortunately, all X1900 series cards are double width cards; the additional width is needed to properly cool the GPU.