The NVIDIA GeForce GTX 660 Review: GK106 Fills Out The Kepler Family
by Ryan Smith on September 13, 2012 9:00 AM ESTCompute Performance
As always our final set of real-world benchmarks is composed of a look at compute performance. As we have seen with GTX 680 and GTX 670, Kepler appears to be significantly less balanced between rendering and compute performance than GF110 or GF114 were, and as a result compute performance suffers. Further compounding this is the fact that GK106 only has 5 SMXes versus the 8 SMXes of GK104, which will likely further depress compute performance.
Our first compute benchmark comes from Civilization V, which uses DirectCompute to decompress textures on the fly. Civ V includes a sub-benchmark that exclusively tests the speed of their texture decompression algorithm by repeatedly decompressing the textures required for one of the game’s leader scenes. Note that this is a DX11 DirectCompute benchmark.
It’s interesting then that despite the obvious difference between the GTX 660 and GTX 660 Ti in theoretical compute performance, the GTX 660 actually beats the GTX 660 Ti here. Despite being a compute benchmark, Civlization V’s texture decompression benchmark is more sensitive to memory bandwidth and cache performance than it is shader performance, giving us the results we see above. Given the GTX 660 Ti’s poor showing in this benchmark this is a good thing for NVIDIA since this means they don’t fall any farther behind. Still, the GTX 660 is effectively tied with the 7850 and well behind the 7870.
Our next benchmark is SmallLuxGPU, the GPU ray tracing branch of the open source LuxRender renderer. We’re now using a development build from the version 2.0 branch, and we’ve moved on to a more complex scene that hopefully will provide a greater challenge to our GPUs.
SmallLuxGPU sees us shift towards an emphasis on pure compute performance, which of course is going to be GTX 660’s weak point here. Over 2 years after the launch of the GTX 460 and SLG performance has gone exactly nowhere, with the GTX 460 and GTX 660 turning in the same exact scores. Thank goodness the 8800GT is terrible at this benchmark, otherwise the GTX 660 would be in particularly bad shape.
It goes without saying that with the GTX 660’s poor compute performance here, the 7800 series is well in the lead. The 7870 more than trebles the GTX 660’s performance, an indisputable victory if there ever was one.
For our next benchmark we’re looking at AESEncryptDecrypt, an OpenCL AES encryption routine that AES encrypts/decrypts an 8K x 8K pixel square image file. The results of this benchmark are the average time to encrypt the image over a number of iterations of the AES cypher.
Our AES benchmark was one of the few compute benchmarks where the GTX 660 Ti had any kind of lead, but the significant loss of compute resources has erased that for the GTX 660. At 395ms it’s a hair slower than the 7850, never mind the 7870.
For our next benchmark we’re looking at AESEncryptDecrypt, an OpenCL AES encryption routine that AES encrypts/decrypts an 8K x 8K pixel square image file. The results of this benchmark are the average time to encrypt the image over a number of iterations of the AES cypher.
The fluid simulation is another benchmark that includes a stronger mix of memory bandwidth and cache rather than being purely dependent on compute resources. As a result the GTX 660 still trails the GTX 660 Ti, but by a great amount. Even so, the GTX 660 is no match for the 7800 series.
Finally, we’re adding one last benchmark to our compute run. NVIDIA and the Folding@Home group have sent over a benchmarkable version of the client with preliminary optimizations for Kepler. Folding@Home and similar initiatives are still one of the most popular consumer compute workloads, so it’s something NVIDIA wants their GPUs to do well at.
As we’ve seen previously with GK104, this is one of the few compute benchmarks that shows any kind of significant performance advantage for Little Kepler compared to Little Fermi. GTX 660 drops by 12% compared to GTX 660 Ti, but this is still good enough for a 60% performance advantage over GTX 460.
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raghu78 - Thursday, September 13, 2012 - link
Without competition there is no reason for lower pricing. Do you think Nvidia would have cut prices on the GTX 280 if the HD 4870 was not a fantastic performer at less than half the launch price of GTX 280. AMD made Nvidia look silly with their price / performance. Without competition you can see Intel dictate pricing in the CPU market. are you so naive that you believe any company will willingly give away profits and margins when there is no competition.You only need to look back when Nvidia milked the market with its Geforce 8800 Ultra because AMD flopped with R600 aka HD 2900XT. 850 bucks for a single GPU card.http://www.anandtech.com/show/2222
chizow - Friday, September 14, 2012 - link
Sorry I can't fully agree with that statement. As the article mentions, industry leaders must still compete with themselves in order to continue moving product. For years Intel has continued to excel and innovate without any real competition from AMD but now they are starting to feel the hit to their sales as their pace of innovation has slowed in recent years.AMD made a mistake with their 4870 pricing, they went for market share rather than margins and admitted as much in the RV770 Story here on Anandtech. But all they have to show for that effort is quarter after quarter and year after year of unprofitability. They've since done their best to reverse their fortunes by continuously increasing the asking prices on their top tier SKUs, they chose an incredibly poor time to step into "Nvidia Flagship" pricing territory with Tahiti.
If anything, Tahiti's lackluster performance and high price tag relative to 40nm parts enabled Nvidia to offer their midrange ASIC (GK104) as a flagship part. Only now has the market begun to correct itself as it became clear the asking price on 28nm could not justify the asking prices as the differences in performance between 28nm and 40nm parts became indistinguishable. And who led that charge? Nvidia with Kepler. AMD simply piggy-backed price and performance of 40nm which is why you see the huge drops in MSRP since launch for AMD parts.
Bringing the discussion full circle, Nvidia knows full well they are competing with themselves even if you take AMD out of the picture, which is why they compare the GTX 660 to the GTX 460 and 8800GT. They fully understand they need to offer compelling increases in performance at the same price points, or the same performance at much cheaper prices (GTX 660 compared to GTX 570) or there is no incentive for their users to upgrade.
Ananke - Thursday, September 13, 2012 - link
Today's AMD prices are so-so OK, especially considering the street prices and bundles.This GTX660 is priced a little too high, this should've been the GTX670 launch price. The 660 is worth to me around $189 today. I don't understand why people pay premium fro the name. I understand that you may want better driver support under Linux, but for the Windows gamer there is no reason.
The AMD 7870 is still better buy for the money today.
While many people with very old hardware may jump in at this price level, I will pass and wait for the AMD8xxx series. We are almost there :).
The last two years have been very disappointing in the hardware arena. :(
rarson - Friday, September 14, 2012 - link
Yeah, "we've been over this before." Back then you didn't get it, and you still don't because you're not examining the situation critically and making a rational argument, you're just posting fanboy nonsense. AMD's 28nm parts were expensive because:1. They were the first 28nm parts available.
2. 28nm process was expensive (even Nvidia admits that the cost to shrink has been higher and slower-ramping than previous shrinks).
3. Wafers were constrained (SoC manufacturers were starting to compete for wafers; this is additional demand that AMD and Nvidia didn't usually have to compete for).
4. When you have limited supply and you want to make money, which is the entire point of running a business, then you have to price higher to avoid running out of stock too quickly and sitting around with your thumb up your ass waiting for supply to return before you can sell anything. That's exactly what happened when Nvidia launched the 680. Stock was nonexistent for months.
The fact of the matter is that pricing is determined by a lot more things than just performance and you refuse to accept this. That is why you do not run a business.
chizow - Friday, September 14, 2012 - link
And once again, you're ignoring historical facts and pricing metrics from the exact same IHVs and fab (TSMC):1) 28nm offered the lowest increase in price and performance of any previous generation in the last 10 years. To break this down for you, if what you said was actually true about new processes (its not), then 28nm increase in performance would've been the expected 50-100% increase you would expect from 100% of the asking price relative to previous generation. Except it wasn't, it was only 30-40% for 100% of the price relative to Nvidia's parts, and in AMD's case, it was more like +50% for 150% of the asking price compared to last-gen AMD parts. That is clearly asking more for less relative to last-gen parts.
2) Getting into the economics of each wafer, Nvidia would've been able to offset any wafer constraints due to the fact GK104's midrange ASIC size was *MUCH* smaller at ~300mm^2 compared to the usual 500mm^2 from their typical flagship ASICs. This clearly manifested itself in Nvidia's last 2 quarters since GK104 launched where they've enjoyed much higher than usual profit margins. So once again, even if they had the same number of wafer's allocated at 28nm launch as they did at 40nm or 55nm or 65nm, they would still have more chips per wafer. So yes, while the 680 was supply constrained (artificial, imo), the subsequent 670, 660Ti and 660 launches clearly did not.
3) Its obvious you're not much of an economist, financier, hell, even good with simple arithmetic, so stop trying to play armchair CEO. Here are the facts: AMD cards have lost 30-40% of their value in the last 3-4 months, all because Kepler has rebalanced the market to where it should've been from the outset. If that sounds reasonable to you then you probably consider Facebook's IPO a resounding success.
4) Tahiti parts were a terrible purchase at launch and only now are they even palatable after 3 significant price drops forced by the launch of their Kepler counterparts. The answer to why they were a terribl purchase is obvious. They offered too little improvement for similar asking prices relative to 40nm parts. Who in their right mind would defend a 7870 offering GTX 570 performance at GTX 570 prices some 20 months after the 570 launched? Oh right, Rarson would....
rarson - Tuesday, September 18, 2012 - link
1. There's no such thing as "pricing metrics." Prices are NOT determined by past prices! You are a such a moron. THESE ARE NEW PARTS! They use a NEW PROCESS! They cost more! GET OVER IT!2. "Getting into the economics of each wafer"
You are not allowed to talk about economics. You have already aptly demonstrated that you don't have a clue when it comes to economics. So any time you use the word, I'm automatically ignoring everything that comes after it.
3. Everything you said next to the number 3 has absolutely nothing to do with my comment and isn't even factually correct.
4. Everything you said next to the number 4 has absolutely nothing to do with my comment and isn't even factually correct.
chizow - Tuesday, September 18, 2012 - link
1. Nonsense, you obviously have no background in business or economics, EVERYTHING has pricing metrics for valuation or basis purposes. What do you think the stock markets, cost and financial accounting fundamentals are based upon? Valuation that predominantly uses historical data and performance numbers for forward looking performance EXPECTATIONS. Seriously, just stop typing, every line you type just demonstrates the stupidity behind your thought processes.2. Sounds like deflection, you brought fab process pricing into the mix, the fact remains Nvidia can crank out almost 4x as many GK104 for each GF100/110 chip from a single TSMC 300mm wafer (this is just simple arithmetic, which I know you suck at) and their margins have clearly demonstrated this (this is on their financial statements, which I know you don't understand). Whatever increase in cost from 28nm is surely offset by this fact in my favor (once again demonstrated by Nvidia's increased margins from Kepler).
3 and 4 are factually correct even though they have nothing to do with your inane remarks, just run the numbers. Or maybe that's part of the problem, since you still seem to think GTX 570/6970 performance at GTX 570/6970 prices some 18 months later is some phenomenal deal that everyone should sidegrade to.
Fact: AMD tried to sell their new 28nm cards at 100% of the performance and 100% of the price of existing 40nm parts that had been on the market for 15-18 months. These parts lost ~30% of their value in the subsequent 6 months since Kepler launched. Anyone who could not see this happening deserved everything they got, congratulations Rarson. :)
CeriseCogburn - Thursday, November 29, 2012 - link
Only he didn't get anything. He was looking to scrape together a 6850 a few weeks back.MySchizoBuddy - Thursday, September 13, 2012 - link
So nvidia choose not to compare the 660 with 560 but with 460. Why is that?Ryan Smith - Thursday, September 13, 2012 - link
I would have to assume because the 660 would be so close to the 560 in performance, and because very few mainstream gamers are on a 1-year upgrade cycle. If you picked up a 560 in 2011 you've very unlikely to grab a 660 in 2012.