From The Top: Shipping The Hunter Before The Tank
Back in the GeForce GTX 400 and 500 days, Nvidia’s marketing came out with this analogy that resonated with me as a recovered WoW addict. It referred to its highest-end parts leveraging GF110 as “tanks,” meaning they came equipped with all of the compute performance and gaming potential enabled by the Fermi architecture. Later, the GF104-based GeForce GTX 460 surfaced with resources better-suited for playable frame rates, sacrificing most of the bigger chip’s double-precision units in the interest of a leaner GPU. The team used the term “hunter” for that one.
Fast-forward to the Kepler generation. When Nvidia introduced GeForce GTX 680, revealed its GK104 roots, and didn’t discuss compute performance at the launch event, everyone suspected something higher-end was waiting in the wings. As we now know, Nvidia needed around 18,000 GK110s to sell to the government in the form of Tesla cards. So, it made the decision to take GK104 to market first, not necessarily knowing how the card that later became GeForce GTX 680 would fare against AMD’s best effort. In retrospect, its approach paid off. But it could have just as easily gone badly.
Nvidia was working on GK110 all the while, and the processor certainly presented significant technical challenges. The original (65 nm) GT200 GPU at the heart of GeForce GTX 280 measured 576 square millimeters. GK110 covers a still-gargantuan 551 mm², but is also composed of 7.1 billion transistors to GT200’s 1.4. I’ve been told that GK110 is the largest chip that TSMC could fabricate at 28 nm, even. So, looking back, delaying Nvidia’s “tank” in the desktop space allowed the company to do the engineering necessary for a high-performance GPU that behaves well thermally and acoustically.
That’s not to say Nvidia’s decision makers knew this was going to be the case right away. Having just come from Fermi (which you’ll remember drove the infamously-hot GeForce GTX 480), Andrew’s team saw the size of the chip Jonah’s team was working on and immediately assumed that GK110 would be a 300 W GPU. The GPU engineers were confident that Kepler would be more power-efficient though, and, in the end, GeForce GTX Titan with its one disabled SMX hit the 250 W Nvidia’s board guys were hoping for.
The board team also planned for GeForce GTX 680’s GK104 processor to be a 250 W part, anticipating that it’d replace GeForce GTX 580’s GF110 at 244 W. As we discovered last March, though, the 680 ended up with a 195 W TDP, pushing up to 225 W or so through GPU Boost. But Andrew and Jonah admit to quite a bit of shared stress at the time, as engineers grappled with the previous generation’s power difficulties, what they believed Kepler could do for efficiency, and AMD’s high-profile transition to the powerful GCN architecture, all at the same time.