Over the past few days, we were hearing rumors from many quarters that AMD's "Tahiti" high-performance GPU may have been a deviation from an older specification, and that it really has 2304 stream processors spread across 40 GCN compute units (CUs), instead of the 32 the Radeon HD 7970 ended up with. Both AMD and NVIDIA create more redundant components on their chips than their SKUs end up getting, so they could increase yields, it's a process commonly known as "harvesting".

On Tuesday, AMD quashed the rumor in an e-mail to Bright Side of News, in which it said that Tahiti XT (Radeon HD 7970) makes use of all the CUs there are, on the chip. The 40 CU / 2308 SP rumor gained some weight with the fact that since AMD is venturing into unknown territory (TSMC's 28 nm process, built after quite some delays and failures), it could do some heavy harvesting. Examples of harvesting in recent past include Intel Sandy Bridge-E Core i7 processors, which use only up to 6 out of 8 cores on the silicon, and only up to 15 MB out of 20 MB available on it; and GeForce GTX 480, which used only 480 out of 512 CUDA cores available on the GF100 GPU.