Sizing 'em up
Take some clock speed information and some other numbers about per-clock capacity from the latest crop of high-end graphics cards, and you get this neat table:
|Radeon R9 290X||64||176/88||4.0||5.6||320|
|Radeon R9 Fury||64||224/112||4.0||7.2||512|
|Radeon R9 Fury X||67||269/134||4.2||8.6||512|
|GeForce GTX 780 Ti||37||223/223||4.6||5.3||336|
|Gigabyte GTX 980||85||170/170||5.3||5.4||224|
|MSI GeForce GTX 980 Ti||108||216/216||7.4||6.9||336|
|GeForce Titan X||103||206/206||6.5||6.6||336|
|GeForce GTX 1080||111||277/277||6.9||8.9||320|
Those are theoretical peak capabilities for each of the measures above. We won't be testing every card in the table, but we're leaving some older cards in to show how far we've come since Kepler. As you can see, the GTX 1080 provides a nice increase in pretty much every measure over GM204 and the GTX 980, and it's even better in some regards than the GM200 GPU on board the Titan X and GTX 980 Ti. Let's see how our calculations hold up with some tests from the Beyond3D suite.
The GTX 1080 has the same number of ROPs as the GTX 980, but its substantially higher clocks and higher SM count allow it to deliver a substantial increase in pixel fill rate over that card, pushing past even the GM200-powered GeForce GTX 980 Ti. Good grief.
This bandwidth test measures GPU throughput using two different textures: an all-black surface that's easily compressed and a random-colored texture that's essentially incompressible. Throw an incompressible texture at the GTX 1080, and it produces a nice boost over the GTX 980. The GTX 980 Ti still comes pretty close, though, and the Fiji cards pull ahead. Once the card can take advantage of its compression mojo, however, the amount of throughput gets a little ridiculous. It appears the new delta-color-compression techniques Nvidia implemented in Pascal are definitely doing their thing.
All of the graphics cards tested come close to hitting their peak texture-filtering rate in this test. The GTX 1080 edges out the prodigious power of the R9 Fury X here, and it holds that lead both with simple and more complicated formats. It also speeds way past the GTX 980 and GTX 980 Ti, for the most part. In fact, we can already say that the GTX 980 Ti is the GTX 1080's most natural competitor in these tests—the GTX 980 just can't keep up.
As we've seen in past reviews, our GeForce cards actually slightly exceed their theoretical peaks in this polygon throughput test—substantially so, in the case of the GeForce GTX 1080. We've guessed that this test is especially amenable to GeForces' GPU Boost feature in the past, so it's possible the cards are just running really fast. Regardless, the GTX 1080 turns in some impressive numbers.
The situation is more normal in our ALU throughput tests, where all of the cards more or less hit their peak theoretical numbers.
All told, the GeForce GTX 1080 is an exceptionally potent graphics card by every theoretical measure we can throw at it. Let's see how that performance carries over to some real games.