The reference ATI Radeon HD 4670 graphics card is much smaller than the Radeon HD 4800 series when it comes to the PCB size and isn't much different from the earlier ATI Radeon HD 3600 series. The cooling solution on the Sapphire version occupies a single slot and contains a single fan approximately 70mm in size. This fan though is only powered by a two-wire cable compared to four wires on the reference model and other newer graphics cards. A sticker showcasing Sapphire Technology's fictional graphics girl, the company's logo and URL, and then the model of this graphics card covers the front of this graphics card.
The RV730XT core used by the Radeon HD 4670 is built on a 55nm fabrication process, its reference clock is 750MHz, contains 320 unified shader pipelines, its peak memory bandwidth is 32 GB/s, and supports Unified Video Decoder 2. There is no heatsink covering any of the memory ICs on either side of the graphics card. The memory used by the Sapphire HD 4670 is made by Hynix with a part number of H5RS5223CFR, which is rated to operate at 1000MHz. The Radeon HD 4670 uses GDDR3 memory (a step-down from the GDDR5 used by the Radeon HD 4870) with a 128-bit interface.
The Radeon HD 4600 series is CrossFireX compatible, which means you can connect up to four ATI GPUs together to split the rendering workload. ATI CrossFire support came to Linux just last month, however, with the current implementation the Linux driver supports sharing the graphics workload just between two GPUs. No CrossFire testing is being done in this article though due to only having one Sapphire Radeon HD 4670.