The biggest disadvantage of AMD’s new Radeon HD 6790 was that the ROPs were cut in half, these handle the raster operations and carry a big burden in 3D games. But the specified number of 16 ROPs looks to have transformed into 24 when partners are shipping their cards to stores.
Exactly what went wrong is uncertain, but most likely it was a miscommunication that means that man, if not all, partners are shipping Radeon HD 6790 with too many active ROPs. Barts has 32 ROPs to begin with, but the idea was to cut these in half, as with Radeon HD 5770, to lower performance reduce the price compared to Radeon HD 6800.
Now that several shipments of Radeon HD 6790 have been shipped with 50% more ROPs AMD could have a problem with price matching when performance of the new mid-range cards will be higher than anticipated.
Whether the cards that went to the media had 16 or 24 ROPs is unclear, but most likely it was the latter. At the same time it is uncertain how AMD will handle the situation and according to TechPowerUp it is currently doing a survey to see what went wrong and to what extent the 24 ROPs circuits have spread. According to AMD partners it seems like most Radeon HD 6790 circuits have 24 active ROPs.
To consumers AMD’s blunder is pure profit, but the risk is that new Radeon HD 6790 cards will be slower than those available now. We will know more when AMD makes an official statement. Either way it is kind of ironic to learn of this when AMD recently denied the unclocking of Radeon HD 6790.
