AMD could be moving towards xx5 donominators say 480 and then later on a 485 for their graphics card series, indicating faster models compared to 0 suffix based models. The company also reaffirms the arrival of the Radeon RX 490 model.

These xx5 revisions may actually be released after the initial batches and this are released after the current line of available products, thus these would be updated GPUs with say optimizations on 14nm FinFET chips for higher clock speeds and lower consumption. While AMD hasn't confirmed this is the case it certainly is indicative. So inevitable you might see say a Radeon RX 485 with the 4 for Generation, the 8 is the tier and the 5 being the revision. Striking is the mention of the '9', which AMD again the arrival of the RX 490 card confirms indirectly.

Tier versus performance things wil look like this, and if you look closely at the slide you can see the xx5 shown under 'Revision':

 
You can also spot the Tier 9 in there indicating Radeon RX 490, it is listed with a 256-bit  wide (or higher) memory bus and tagged as a 4K capable graphics cards. AMD has not officially confirmed of the revisions, but pointed to the possibility of it with this slide.

AMD possibly will be using XX5 revisions e.g. AMD Radeon RX 495