The limitation seems to be based around the reference design used for the RX 480.
AMD’s RX 480 is about 2 days away from being readily available via various outlets and while the flow of information regarding the first Polaris 10 based chip has more or less been generous over time, we are constantly finding out more about the card prior to its June 29th release date.
With as much as 25 times available stock at some retailers, AMD’s RX400 series lineup, starting with the RX480 are expected to be much more readily available to the mass market than competing higher-end solutions from Nvidia, the GTX 1070 and GTX 1080 which command a significant premium as 3rd party sellers offer them at significantly higher prices than retail.
While initial reports and benchmarks placed the RX 480 able to push past the 1.5-1.6 GHZ barrier with ease, it might be a longer wait for consumers wanting to see those gains as it seems that the stock cards, which will be available later this week are to be restricted to just around 1.4 GHZ, up from a base clock of 1120 MHz and a standard boost clock of 1266 MHz for the reference edition. There are, of course reference cards that are clocked significantly higher. For example, the XFX RX480 comes with a 1328 MHz clock speed out of the box. AMD’s official overclocking utility, Radeon WattMan, previously known as AMD overdrive is also being offered to users willing to coax more performance out of their GPUs.
The RX 480 however seems to have hardware restrictions in play that prevent it from clocking above 1400 MHz with the highest recorded clock on the GPU currently sitting at 1379 MHZ. This might simply be a power draw limitation or potentially an overclock limit for the GPU on AMD’s part. While unexpected, it would make sense in a way given that AMD might be planning a Polaris 10 based higher end sibling for the RX 480 in the coming days and since the architecture itself looks more or less at its peak via the RX 480, the performance gains to be made could be via a higher base clock and mover overclocking support. Another possibility is that AIB solutions which will have higher clocks may not have such restrictions. Nevertheless, the RX 480, at its price point of $199 seems to be the best price performance offering over the past 2 years in the industry and a clock limitation under 1.4 GHZ does not do much to eliminate its prospects.