AMD is probably going to release RX 5600 video cards and the variants of ASRock seem to get 6GB of vram. This is evident from a reference to ASRock of the RX 5600 and RX 5600XT at the Eurasian Economic Commission. An Asus reference mentions RX 5600 cards with 8GB.
The report of ASRock and Asus cards with both the RX 5600 and RX 5600XT GPUs was noticed by Videocardz. Based on the indications, it is clear that both cards come in two ASRock variants with 6GB vram, probably gddr6. At Asus, according to the report, it would be 8GB of RAM for the RX 5600 and 5600XT, although it does not seem very likely.
In addition, the information shows that the RX 5500XT and the regular RX 5500 video cards come in versions with 4 and 8 GB vram. AMD presented the Radeon 5500 GPU in October and then announced that there would be versions with 4 and 8 GB. That also seems to apply to the 5500XT.
ASRock would release the RX 5500XT, 5600 and 5600XT in its Challenger and Phantom series; the RX 5500 is not mentioned in the mention of ASRock. Asus is said to be releasing the four different cards in up to three different series, including Rog Strix and Dual Evo.
Earlier, Videocardz reported based on sources that the RX 5600XT would be released early next year, perhaps in January. It is not clear when the RX 5600 should appear; the RX5500XT would be announced this week. Images of custom RX 5500XT video cards from ASRock and Gigabyte have also appeared recently.