The 2GB of onboard GDDR5 memory still runs at the same bogglingly fast 6GHz, and there have been no compromises with the bus, which remains at 256-bit. Indeed, some might argue that it has been overly generous: of the eight "SMX" units in the GTX 680 (each unit containing 192 CUDA cores), only one of them has been disabled. The GTX 670 is intriguing in that NVIDIA has been somewhat conservative with the cutbacks. In the past, enthusiasts and hackers alike have been successful in reactivating some of the disabled features - though often they don't work, since the chips are not of the highest quality. In this way, more of the processors produced at the production facility become viable. The usual form for NVIDIA's tier-two product is to cut down the design of the flagship in every meaningful way: fewer active processor cores running at a slower speed, a more restricted memory bus, and slower RAM. Now, with the debut of the newer, cheaper GTX 670, we begin to see what happens with the rest of the production run. In the case of the NVIDIA graphics cards based on the new "Kepler" line, the best processors are reserved for the top-end product - the GTX 680, which received a rapturous review from Digital Foundry last month. So what happens to these less-than-perfect chips? Well, a process called "binning" sorts the processors into various quality levels, each destined for different end-products. Some are capable of running at faster speeds than others, while sometimes defects manifest when the transistors aren't fabricated entirely as they should be, owing to microscopic imperfections in the material. Silicon chip production is not an exact art - no two chips that come off the production line are exactly alike.