The NVIDIA GeForce GTX 660 Review: GK106 Fills Out The Kepler Family
by Ryan Smith on September 13, 2012 9:00 AM ESTAs our regular readers are well aware, NVIDIA’s 28nm supply constraints have proven to be a constant thorn in the side of the company. Since Q2 the message in financial statements has been clear: NVIDIA could be selling more GPUs if they had access to more 28nm capacity. As a result of this capacity constraint they have had to prioritize the high-profit mainstream mobile and high-end desktop markets above other consumer markets, leaving holes in their product lineups. In the intervening time they have launched products like the GK104-based GeForce GTX 660 Ti to help bridge that gap, but even that still left a hole between $100 and $300.
Now nearly 6 months after the launch of the first Kepler GPUs – and 9 months after the launch of the first 28nm GPUs – NVIDIA’s situation has finally improved to the point where they can finish filling out the first iteration of the Kepler GPU family. With GK104 at the high-end and GK107 at the low-end, the task of filling out the middle falls to NVIDIA’s latest GPU: GK106.
As given away by the model number, GK106 is designed to fit in between GK104 and GK107. GK106 offers a more modest collection of functional blocks in exchange for a smaller die size and lower power consumption, making it a perfect fit for NVIDIA’s mainstream desktop products. Even so, we have to admit that until a month ago we weren’t quite sure whether there would even be a GK106 since NVIDIA has covered so much of their typical product lineup with GK104 and GK107, leaving open the possibility of using those GPUs to also cover the rest. So the arrival of GK106 comes as a pleasant surprise amidst what for the last 6 months has been a very small GPU family.
GK106’s launch vehicle will be the GeForce GTX 660, the central member of NVIDIA’s mainstream video card lineup. GTX 660 is designed to come in between GTX 660 Ti and GTX 650 (also launching today), bringing Kepler and its improved performance down to the same $230 price range that the GTX 460 launched at nearly two years ago. NVIDIA has had a tremendous amount of success with the GTX 560 and GTX 460 families, so they’re looking to maintain this momentum with the GTX 660.
| GTX 660 Ti | GTX 660 | GTX 650 | GT 640 | |
| Stream Processors | 1344 | 960 | 384 | 384 |
| Texture Units | 112 | 80 | 32 | 32 |
| ROPs | 24 | 24 | 16 | 16 |
| Core Clock | 915MHz | 980MHz | 1058MHz | 900MHz |
| Shader Clock | N/A | N/A | N/A | N/A |
| Boost Clock | 980MHz | 1033MHz | N/A | N/A |
| Memory Clock | 6.008GHz GDDR5 | 6.008GHz GDDR5 | 5GHz GDDR5 | 1.782GHz DDR3 |
| Memory Bus Width | 192-bit | 192-bit | 128-bit | 128-bit |
| VRAM | 2GB | 2GB | 1GB/2GB | 2GB |
| FP64 | 1/24 FP32 | 1/24 FP32 | 1/24 FP32 | 1/24 FP32 |
| TDP | 150W | 140W | 64W | 65W |
| GPU | GK104 | GK106 | GK107 | GK107 |
| Transistor Count | 3.5B | 2.54B | 1.3B | 1.3B |
| Manufacturing Process | TSMC 28nm | TSMC 28nm | TSMC 28nm | TSMC 28nm |
| Launch Price | $299 | $229 | $109 | $99 |
Diving right into the guts of things, the GeForce GTX 660 will be utilizing a fully enabled GK106 GPU. A fully enabled GK106 in turn is composed of 5 SMXes – arranged in an asymmetric 3 GPC configuration – along with 24 ROPs, 3 64bit memory controllers, and 384KB of L2 cache. Design-wise this basically splits the difference between the 8 SMX + 32 ROP GK104 and the 2 SMX + 16 ROP GK107. This also means that GTX 660 ends up looking a great deal like a GTX 660 Ti with fewer SMXes.
Meanwhile the reduction in functional units has had the expected impact on die size and transistor count, with GK106 packing 2.54B transistors into 214mm2. This also means that GK106 is only 2mm2 larger than AMD’s Pitcairn GPU, which sets up a very obvious product showdown.
In breaking down GK106, it’s interesting to note that this is the first time since 2008’s G9x family of GPUs that NVIDIA’s consumer GPU has had this level of consistency. The 200 series was split between 3 different architectures (G9x, GT200, and GT21x), and the 400/500 series was split between Big Fermi (GF1x0) and Little Fermi (GF1x4/1x6/1x8). The 600 series on the other hand is architecturally consistent from top to bottom in all respects, which is why NVIDIA’s split of the GTX 660 series between GK104 and GK106 makes no practical difference. As a result GK104, GK106, and GK107 all offer the same Kepler family features – such as the NVENC hardware H.264 encoder, VP5 video decoder, FastHDMI support, TXAA anti-aliasing, and PCIe 3.0 connectivity – with only the number of functional units differing.
As GK106’s launch vehicle, GTX 660 will be the highest performing implementation of GK106 that we expect to see. NVIDIA is setting the reference clocks for the GTX 660 at 980MHz for the core and 6GHz for the memory, the second to only the GTX 680 in core clockspeed and still the same common 6GHz memory clockspeed we’ve seen across all of NVIDIA’s GDDR5 desktop Kepler parts this far. Compared to GTX 660 Ti this means that on paper GTX 660 has around 76% of the shading and texturing performance of the GTX 660 Ti, 80% of the rasterization performance, 100% of the memory bandwidth, and a full 107% of the ROP performance.
These figures mean that the performance of the GTX 660 relative to the GTX 660 Ti is going to be heavily dependent on shading and rasterization. Shader-heavy games will suffer the most while memory bandwidth-bound and ROP-bound games are likely to perform very similarly between the two video cards. Interestingly enough this is effectively opposite the difference between the GTX 670 and GTX 660 Ti, where the differences between the two of those cards were all in memory bandwidth and ROPs. So in scenarios where GTX 660 Ti’s configuration exacerbated GK104’s memory bandwidth limitations GTX 660 should emerge relatively unscathed.
On the power front, GTX 660 has power target of 115W with a TDP of 140W. Once again drawing a GTX 660 Ti comparison, this puts the TDP of the GTX 660 at only 10W lower than its larger sibling, but the power target is a full 19W lower. In practice power consumption on the GTX 600 series has been much more closely tracking the power target than it has the TDP, so as we’ll see the GTX 660 is often pulling 20W+ less than the GTX 660 Ti. This lower level of power consumption also means that the GTX 660 is the first GTX 600 product to only require 1 supplementary PCIe power connection.
Moving on, for today’s launch NVIDIA is once again going all virtual, with partners being left to their own designs. However given that this is the first GK106 part and that partners have had relatively little time with the GPU, in practice partners are using NVIDIA’s PCB designs with their own coolers – many of which have been lifted from their GTX 660 Ti designs – meaning that all of the cards being launched today are merely semi-custom as opposed to some fully custom designs like we saw with the GTX 660 Ti. This means that though there’s going to be a wide range designs with respect to cooling, all of today’s launch cards will be extremely consistent with regard to clockspeeds and power delivery.
Like the GTX 660 Ti launch, partners have the option of going with either 2GB or 3GB of RAM, with the former once more taking advantage of NVIDIA’s asymmetrical memory controller functionality. For partners that do offer cards in both memory capacities we’re expecting most partners to charge $30-$40 more for the extra 1GB of RAM.
NVIDIA has set the MSRP on the GTX 660 at $229, which NVIDIA’s partners will be adhering to almost to a fault. Of the 3 cards we’re looking at in our upcoming companion GTX 660 launch roundup article, every last card is going for $229 despite the fact that every last card is also factory overclocked. Because NVIDIA does not provide an exhaustive list of cards and prices it’s not possible to say for sure just what the retail market will look like ahead of time, but at this point it looks like most $229 cards will be shipping with some kind of factory overclock. This is very similar to how the GTX 560 launch played out, though if it parallels the GTX 560 launch close enough then reference-clocked cards will still be plentiful in time.
At $229 the GTX 660 is going to be coming in just under AMD’s Radeon HD 7870. AMD’s official MSRP on the 7870 is $249, but at this point in time the 7870 is commonly available for $10 cheaper at $239 after rebate. Meanwhile the 2GB 7850 will be boxing in the GTX 660 in from the other side, with the 7850 regularly found at $199. Like we saw with the GTX 660 Ti launch, these prices are no mistake by AMD, with AMD once again having preemptively cut prices so that NVIDIA doesn’t undercut them at launch. It’s also worth noting that NVIDIA will not be extending their Borderlands 2 promotion to the GTX 660, so this is $229 without any bundled games, whereas AMD’s Sleeping Dogs promotion is still active for the 7870.
Finally, along with the GTX 660 the GK107-based GTX 650 is also launching today at $109. For the full details of that launch please see our GTX 650 companion article. Supplies of both cards are expected to be plentiful.
| Summer 2012 GPU Pricing Comparison | |||||
| AMD | Price | NVIDIA | |||
| Radeon HD 7950 | $329 | ||||
| $299 | GeForce GTX 660 Ti | ||||
| Radeon HD 7870 | $239 | ||||
| $229 | GeForce GTX 660 | ||||
| Radeon HD 7850 | $199 | ||||
| Radeon HD 7770 | $109 | GeForce GTX 650 | |||
| Radeon HD 7750 | $99 | GeForce GT 640 | |||
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chizow - Tuesday, September 18, 2012 - link
Where did I call you an idiot? You took issue with my response to rarson, who fits my profile as someone who continuously ignores or is unable to understand some very simple concepts backed by mounds of evidence and historical data.Then he has the gall to question my ability to understand certain concepts? Of course I have trouble understanding opinions founded on stupidity. Unless you have the same problems, why would you take offense?
CeriseCogburn - Thursday, November 29, 2012 - link
Here, I'll call him an idiot and a liar.He's an idiot and a liar.
He's been one forever.
It will never change.
As least David's butt is smakc full of his lipstick, and poor Goliath is rich as can be and the one still standing and alive.
I guess Galidou sucked too hard now David (amd) is almost dead.
Poor Galidou, supporting the underdog under it's jockstrap just hasn't worked out at all.
I have a feeling David's paramour might be a bit "upset" again, and again, and again, and again, and again.
Did the idiot get anything correct ?
Were his correction to his incorrect comments that he corrected not needed anyway since even after the corrections he issued to himself he was still wrong?
I'll answer that.
YES.
Galidou - Monday, September 17, 2012 - link
http://www.techpowerup.com/reviews/NVIDIA/GeForce_...20% more performance than last gen for the same price one year and a half later isn't a big deal either. Sure you win on thermal and consumption constraints.
You don't even know me personally and still you have to insult my intelligence, that's what fanboys do... and that's far worse than lacking of judgement in my opinion.
I admit that AT LAUNCH the 7970 was worse than the gtx 280 compared to last gen parts but you have to consider what's coming out too. And we all know they have this kind of information, and estimation of the performance of the part for the price.
So right, they should of priced 7970 400$ but that would of made another war with Nvidia(which already sued AMD for price fixing between them) so this price might just reflect the return to normal for both companies. No more 4870 BIG DEAL, back to normal, not because AMD want to price it BADLY because they have been sued to do so....
Galidou - Monday, September 17, 2012 - link
You get the first shot on new technology, you price it higher, you lower the price when the new stuff comes out. Same laws for both companies. 4870 was an unknown mistake, the chip wasn't out and the preliminary tests showed it performing way less than when it launched.It was a precipitated launch. Prices had been fixed WAY before the final product. With drivers enhancements and such the 4870 performed WAY above what AMD was hoping for, it was a surprise to them. They couldn't play too much with the price because it was already out in the medias for a while. Shit happens, they have been sued for being lucky with their final products for price fixin and next gen cards AHD to go up in prices breaking the amazing deal they sold for.
chizow - Tuesday, September 18, 2012 - link
"I admit that AT LAUNCH the 7970 was worse than the gtx 280 compared to last gen parts but you have to consider what's coming out too."Finally, now was that so hard?
Galidou - Monday, September 17, 2012 - link
Worst increase in performance, not, gtx 680 is 20-25% average faster than gtx 580. Biggest increase in price, sure but do you know anything about price fixing between AMD and Nvidia, yep, the prices are fixed by both companies.Even if they were sued just before the days of radeon 4870 and gtx 280(thus explaining in part why the price of the 4870 wasn't adjusted to Nvidia because they were forbid to and were being checked) they continue to do that.
Galidou - Monday, September 17, 2012 - link
While speaking about all that, pricing of the 4870 and 7970 do you really know everything around that, because it seems not when you are arguing, you just seem to put everything on the shoulder of a company not knowing any of the background.Do you know the price of the 4870 was already decided and it was in correlation with Nvidia's 9000 series performance. That the 4870 was supposed to compete against 400$ cards and not win and the 4850 supposed to compete against 300$ series card and not win. You heard right, the 9k series, not the GTX 2xx.
The results even just before the coming out of the cards were already ''known''. The real things were quite different with the final product and last drivers enhancements. The performance of the card was actually a surprise, AMD never thought it was supposed to compete against the gtx 280, because they already knew the performance of the latter and that it was ''unnaittanable'' considering the size of the thing. Life is full of surprise you know.
Do you know that after that, Nvidia sued AMD/ATI for price fixing asking for more communications between launch and less ''surprises''. Yes, they SUED them because they had a nice surprise... AMD couldn't play with prices too much because they were already published by the media and it was not supposed to compete against gtx2xx series. They had hoped that at 300$ it would ''compete'' against the gtx260 and not win against i thus justifying the price of the things at launch. And here you are saying it's a mistake launching insults at me, telling me I have a low intelligence and showing you're a know it all....
Do you know that this price fixing obligation is the result of the pricing of the 7970, I bet AMD would of loved to price the latter at 400$ and could do it but it would of resulted in another war and more suing from Nvidia that wanted to price it's gtx 680 500$ 3 month after so to not break their consumers joy, they communicate A LOT more than before so everyone is happy, except now it hurts AMD because you compare to last gen and it makes things seems less of a deal. But with things back to normal we will be able to compare last gen after the refreshed radeon 7xxx parts and new gen after that.
Nvidia the ''giant'' suing companies on the limit of ''extinction'', nice image indeed. Imagine the rich bankers starting to sue people in the streets, and they are the one you defend so vigorously. If they are that rich, do you rightly think the gtx 280 was well priced even considering it was double the last generation... It just means one thing, they could sell their card for less money but instead they sue the other company to take more money from our pockets, nice image.... very nice..... But that doesn't mean I won't buy an Nvidia card, I just won't defend them as vigorously as you do.... For every Goliath, we need a David, and I prefer David over Goliath.... even if I admire the strenght of the latter....
Galidou - Monday, September 17, 2012 - link
I was wrong, Nvidia didn't sue over AMD, both companies were sued for price fixing but things are back now, anyway all this stuff is taking way too much of my time, you have your way of seeing things as facts, I have my way of seeing things as my opinion, I'll give you the benefit of the doubt because you're so much more intelligent than me and I don't care about the ultimate truth as I don't beleive in such a thing.Being sued back in 2008 in the times they were working on gtx2xx and 4870 series might explain the lack of information on each others and the reason why they couldn'T play with the price once they knew the surprise. They were probably forbid to adjust price based on each other performance for the benefit of the consumer. But the surprise of that SO small chip performing sometimes better than a gpu 110% bigger was a real shock for the small company.
CeriseCogburn - Wednesday, September 19, 2012 - link
You truly are an estrogen doused total licker bleeding red that no tamp can ever stop.Thanks for the pathetic entertainment.
Now you may whine some more in your sensitive little girl voice.
Galidou - Thursday, September 20, 2012 - link
Wow, chizow's acolyte is back. I guess it's his troll name and when he can'T stand it anymore he logs with CeriseCogburn to insult people so he Chizow's name remain clean.Who's whining, when I read you, it seems that's all you can do whine whine whine.... read everything you ever wrote in the last 6 months and that's ALL you do insulting people and whining.... look in the mirror dude.