The GTX 670 Arrives – is it a game changer?

Nvidia has just released the $399 GeForce GTX 670 based on its brand new 28nm Kepler DX11.1 architecture today. This new GPU is the third in Nvidia’s lineup, after the dual-GPU $1000 Flagship GTX 690 and the $500 GTX 680. To properly bring you this review we are going to cover the history of Kepler and why Nvidia is competing with GK104 instead of GK110, and we’ll give you an insider behind-the-scenes look at what probably went on inside AMD and inside Nvidia that set up for today’s launch. And of course, we are focusing on the performance of the GTX 680 and the HD 7970 to see where the new GTX 670 fits in.

The GTX 670 is Nvidia’s replacement for the GTX 570 which launched at the beginning of 2011 at $379. This time, Nvidia is aiming for slightly less than GTX 680 performance in a “value” package to directly compete with AMD’s top cards, the HD 7970 and the HD 7950. The reference HD 7970 is now selling for $480 after a major price drop down from $550 in response to the GTX 680. This is the third time in less than two months that Nvidia is again bringing out a faster card than or nearly equal in performance to AMD’s flagship HD 7970 – and this time the GTX 670 is selling for $80 less than the HD 7970.

So you will see us pit the reference GTX 670, both stock and overclocked, against our PowerColor reference design HD 7970 (above right) and also against the stock GTX 680 (above left) using 18 modern games and 3 synthetic benchmarks mostly using 1920×1200 and 2560×1600 resolutions.

We are also comparing the performance of our last generation reference top single-GPU video cards, HD 6970 and the GTX 580 as they are the fastest video cards of AMD’s and Nvidia’s last 40nm generation.  We are also tossing into the mix, the GTX 570 as it is being replaced by the GTX 670.  The only difference is that the GTX 570 launched at $20 less, for $379 and it was positioned mostly against the AMD flagship HD 6970 also at the same price; and it was also positioned against the HD 6950. This time the $399 GTX 670 is positioned against the (now discounted to) $480 AMD flagship, HD 7970 and also against the HD 7950.  Naturally we want to know if the HD 7970 is worth $80 more as most of them also now come with game bundles.

We will use 18 games and three synthetic benchmarks to compare our cards at 1920×1200 and 2560×1600. We shall also compare Nvidia’s 3-panel Surround working now off of a single GTX 670 at 5760×1080 resolution versus the HD 7970 running Eyefinity at the same resolution. Lastly, we also bench 3D Vision 2 and PhysX, ‘on’ versus ‘off’ at the very popular 1920×1080 resolution.

History of Nvidia’s Kepler and why it is based on GF104 and not GF110

There are a lot of misconceptions about why Nvidia brought out a GK104 256-bit bus high end card built on GF104 to replace the 384-bit flagship card, the GTX 580, built on Fermi’s GF110 design.  Last Autumn, it was not well known outside the industry, but well-known to AMD that Nvidia was complaining that TSMC simply could not build a 450nm “large die” on the 28nm process in time for them to compete with AMD’s upcoming Tahiti.

AMD expected that Nvidia would be very late as they were certain that the large die “Big Kepler” was impossible to produce until Q2 or Q3.  What they did not realize was that Nvidia was also working on GK104 to replace the very popular GF104 that featured the highly efficient GTX 560 Ti.  Evidently, Nvidia was originally planning to meet AMD with a “GTX 570 Ti” type card, so as to at least be close in performance to what they expected the HD 7970 to be. There was some quiet celebration at the end of last year that insiders noted as Nvidia apparently could not believe that AMD had brought out Tahiti under-performing compared to what they were expecting.  Nvidia may have really thought at the time of launch that perhaps part of Tahiti was disabled in AMD’s rush to be first as “aggressor” and “predator” as their CEO had boasted not long before.

Well, Nvidia spent the next few weeks refocusing their efforts to make Kepler as cool and as efficient as possible while still beating the HD 7970’s performance.  And because AMD was so certain that Nvidia would be many more months later with Kepler, they priced their 28nm cards at record highs for AMD pricing and they completely abandoned their “sweet spot” pricing in favor of “premium pricing.”

For example, AMD replaced the $379 HD 6970 with the $550 HD 7970 with barely a 33% performance increase – which was low enough for Nvidia to beat with their midrange-now-turned-flagship Kepler GK104 as the reincarnated GTX 680.  Because Nvidia launched the GTX 680 at $500, undercutting AMD’s pricing by $50 and beating AMD’s performance across the board, AMD was forced to discount their reference cards to about $480 from $550.

It is obvious that AMD is still trying to hold on to the $500 pricing with overclocked HD 7970s by increasing the base clocks to about 1000MHz, something easily attainable to anyone with an original reference 925MHz card, but now with less power draw from a more mature process.  This is the same strategy that AMD has employed with Cypress to meet the GTX 480 and with Cayman to meet the GTX 580.  However, this time things are very different and their strategy is much more likely to fail.

Unless AMD has a respin waiting – which means they would have been working on it since December (and this is highly unlikely now, as evidently they really believed that Nvidia would be many months later with Kepler than they were) – they may have lost this round as overclocking simply won’t cut it.  Kepler is more efficient than Tahiti.

What’s New with Kepler’s GTX 670?

Nvidia’s marketing buzzwords for the GTX 680 and GTX 690 launches were, “Faster. Smoother. Richer.” The GTX 670 is also designed for extreme efficiency and high performance.

Faster

The GTX 680’s Kepler architecture has 8 SMX units and 1536 CUDA cores.   In comparison, the more affordable GeForce GTX 670 ships with 1344 CUDA Cores and 7 SMX units.  The memory subsystem of the GeForce GTX 670 is identical to the GTX 680, consisting of four 64-bit memory controllers (256-bit) with 2GB of GDDR5 memory.  The base clock speed of the GeForce GTX 670 is 915MHz. The typical Boost Clock speed is 980MHz.  GeForce GTX 670’s memory speed is 6008MHz data rate.

The Kepler GTX 670 promises better geometry and texture processing than Fermi’s GTX 570 thanks to its improved instruction throughput and redesign. In addition, Nvidia brings “GPU Boost”, a dynamic way to boost clocks speeds and maximize performance for each game.

Smoother

New kinds of anti-aliasing – FXAA and TXAA – now compete with MSAA in terms of IQ while not sacrificing performance. Also, there is a new “Adaptive VSync” that is reduces tearing and stuttering associated with regular VSync. Great hardware needs great software to support it and Nvidia is also a software company.

Richer

For the first time, it is now possible to play games spanning 3 displays in Surround off of a single GeForce GTX 670.  And this time, the GTX 670 brings two dual-link DVI connectors, one HDMI and one DisplayPort connector (for a 4th accessor display) so that only one adapter is needed for any DVI-enabled display for 3-panel Surround.   In contrast, you will generally need two adapters for the HD 7970 to run the competing 3-panel Eyefinity and you may also experience more tearing with the AMD solution.

PhysX has also been improved.  The GeForce GTX 670 reference board measures 9.5″ in length. Two 6-pin PCIe power connectors are required for operation and if you forget to connect them, you will get an on-screen reminder.

How does the $399 GTX 670 compare with its rival, AMD’s HD 7970 at $480, down from $550 last month

This evaluation attempts to analyze and compare GTX 670, GTX 680 and GTX 570 performance. We also include HD 7970 performance as well as AMD’s fastest card of the last generation, their single-GPU HD 6970 and we will probably announce a price to performance winner. We will also look at the details to see what this new Nvidia Kepler enthusiast value GPU brings to the table for nearly four hundred dollars.

The five competing cards

The GTX 670, GTX 680, the GTX 570, the HD 7970, and the HD 6970 are the top single-GPU cards from Nvidia and AMD of this and of the last generation and we will see where they sit in relation to each other.  We believe that it is important to see how much performance increase the GTX 670 has brought over the GTX 570 so as to see if it is a worthy upgrade.

Since we do not want any chance of our CPU “bottlenecking” our graphics, we are testing all of our graphics cards by using our brand new Intel Core i7-3770K at 4.60GHz, 4 GB Kingston DDR3 and a Gigabyte Z77 motherboard. This new motherboard features an 8x + 8x PCIe 3.0 specification for CrossFire/SLI, but we are testing the GTX 670 using a 16x PCIe 3.0 slot. This new Core i7-3770K at 4.8GHz is more than enough to differentiate high end video cards at high resolution and high detail settings.

Before we do performance testing, let’s take a look at the GTX 670 and quickly recap its new Kepler DX11.1 architecture and features.