When AMD launched the Radeon RX 560 back in April, the GPU sported 1024 stream processors inside of 16 compute units. That figure was an increase from the 896 SPs within 14 CUs in the otherwise-similar previous-gen Radeon RX 460. The reference base and boost clocks also received a spec bump from its predecessor's figures. For unclear reasons, though, it seems that some RX 560s will again ship with 896 SPs. AMD recently made some silent updates to the Radeon RX 560's product page that reveal a second, identically-named version with the smaller resource complement.
One needs only take a trip in Archive.org's Wayback Machine to see the old Radeon RX 560 product page and its proclamations of 16 CUs and 1024 SPs. The current version of the page hedges those figures and qualifies the card's performance from a "Peak Performance" of 2.6 TFLOPS to a "Max Performance up to 2600 GFLOPS." The number of ROPs and texture units hasn't changed, and AMD's "up to 1175 MHz" base and "up to 1275 MHz" boost clock claims are also the same as they have been since launch.
Cards bearing the pared-down Polaris 21 chip have already found their way into e-tailers like Newegg. The site has conveniently added a search selection filter to separate greater and lesser Radeon RX 560 cards, but we imagine other stores might not make things as straightforward for their customers. Board manufacturers could have taken this opportunity to clarify the SP count of cards in their product names, but none of the cards we saw specified the figure in their model numbers. For example, Asus' RX-560-O4G can color the screen with a full box of 1024 crayons, while the company's own RX-560-O4G-EVO has only 896 to work with. We don't intend to single out Asus here; other companies' model numbers aren't any more illuminating.
This is the first time anyone on the TR staff can recall a reduction in shader ALU count from a major graphics-card maker without any modification to the product name. AMD has offered Radeon RX 470D and Radeon RX 560D cards with reduced SP counts in the past, and it's also gone the other way by offering Radeon RX 460 chips with 1024 SPs for sale in China earlier this year. Those cards were all clearly marked to represent the change. Nvidia's GeForce GTX 1060 is available in two versions with different shader ALU counts, but those two versions also bear different memory configurations that make them easier to tell apart in the wild.
It appears that consumers will have to closely examine the packaging or product page of any Radeon RX 560 card from here on out to make sure they're getting the resources they expect. All of the 896-SP Radeon cards we see at retailers so far come bearing 4 GB of GDDR5 memory, and their prices aren't appreciably different from the 1024-SP versions. We imagine that 2 GB versions could soon follow, so memory configuration is probably not a reliable way to identify these cut-down GPUs. Keep your eyes open if you're shopping for entry-level graphics cards in the near future.