Gainward GeForce GTX 680 Phantom

Gainward GeForce GTX 680 Phantom Review

On March 22, Nvidia unveiled its first "Kepler"-based graphics card. Branded as the GeForce GTX 680, the card is powered by a 28nm GPU codenamed GK104 that crams 3540 million transistors into a 294mm2 die. That's an improvement from the 40nm GTX 580, which has 540 million fewer transistors yet is almost three times larger, and it partly highlights the overall goal of Kepler: improved efficiency. This refinement is visible in all aspects of the card, not least of which is raw performance. Based on Fermi's third-generation Streaming Multiprocessor (SM) architecture, the GTX 580 has 512 CUDA cores, 48 ROP (Raster Operations) units and 64 TAU (Texture Addressing Units). The GTX 680 ramps that up to a massive 1536 CUDA cores, 128 TAUs and 32 ROPs, bringing loads of horsepower to the race. A few changes have been made to the clock speeds while the Shader clock has been removed entirely. Instead, everything now runs off the core clock, which now also features what Nvidia calls a "Boost Clock," a technology akin to Intel's Turbo Boost. By default, the GTX 680 comes clocked at 1006MHz -- already 30% higher than the reference GTX 580 -- with a dynamically changing Boost Clock of 1058MHz. Meanwhile, the GDDR5 memory frequency has increased 50% from 4008MHz to a blistering 6008MHz.