Overclocking the PowerColor PCS+
To see what kind of extra headroom the PowerColor PCS+ HD 4870 1GB had hiding under the hood, we used the Overdrive control panel built into ATI's drivers to overclock the card beyond its already factory-overclocked state.
In the end, Overdrive topped out at a GPU speed of 830MHz and Memory speed of 950MHz (3.8Gbps effective), which were only modest increases over the card's "stock" 800MHz (GPU) and 900MHz (Memory).
While we had the PowerColor PCS+ HD 4870 1GB overclocked, we re-ran a couple of benchmarks and realized only marginal performance improvements. With a factory overclocked card like this one, it's probably best to leave its frequencies be, for the sake of longevity and reliability.