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GeForce GTX 660 Ti Review: Nvidia's Trickle-Down Keplernomics

GeForce GTX 660 Ti Review: Nvidia's Trickle-Down Keplernomics
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Nvidia's Kepler architecture is finally manifest in a £250 graphics card, which the company says beats AMD's Radeon HD 7870 and challenges its more expensive 7950. Can this GK104-based mainstream card carve out a spot between the GCN-based competition?

More than four months have passed since Nvidia's Kepler architecture was introduced in GeForce GTX 680 (check out GeForce GTX 680 2 GB Review: Kepler Sends Tahiti On Vacation for more information on the design itself). In the five months since, we've seen Nvidia fill up the high-end space with its GeForce GTX 670 and GeForce GTX 690. However, GeForce GT 640 remains the only mainstream board with Kepler's DNA in it. That leaves an almost-£250 range currently filled with older Fermi-based models, such as GeForce GTX 560, 570, and 580. No doubt, newer and more efficient Kepler-derived silicon will take the place of those cards, bringing us today's GeForce GTX 660 Ti launch.

It's common to see the same piece of silicon nipped and tucked to create products aimed at different price points. Companies like AMD and Nvidia play with clock rates, alter memory interfaces, and turn pieces of their GPUs on or off. The GeForce GTX 660 Ti employs the same GK104 processor as GeForce GTX 670. However, Nvidia cuts the card's memory bus down from 256- to 192-bits and removes one of the GPU's four render back-end clusters, leaving everything else intact.

We might have expected Nvidia to detune more of its GK104. However, GeForce GTX 660 Ti employs the same core and memory clocks as GeForce GTX 670. That is to say, like the 670, this new board features seven functional SMX blocks. Consequently, GeForce GTX 660 Ti comes equipped with 1344 CUDA cores and 112 texture units. Each of its three remaining ROP clusters output up to eight 32-bit pixels, totalling 24 pixels per clock. Moreover, three 64-bit memory interfaces aggregate to 192 bits. We expect to see GeForce GTX 660 Ti perform on-par with GTX 670 in compute-oriented apps, but not as well in games.

Beyond its general specifications, GeForce GTX 660 Ti offers the same GPU Boost functionality found on the GTX 670 and 680 cards, support for up to four displays, and TXAA in games that support the feature. Although those two higher-end boards support four-way SLI configurations, Nvidia cuts GeForce GTX 660 Ti back to a maximum of three cards, which is actually something we haven't seen from the company before. Typically, at this price point, we'd expect a two-card maximum.


GeForce GTX 670
GeForce GTX 660 Ti
GeForce GTX 580
Radeon HD 7950
Radeon HD 7870
Shaders1344
1344512
1792
1280
Texture Units
112
11264
112
80
Full Colour ROPs
32
24
48
32
32
Graphics Clock (Base)
915 MHz
915 MHz
772 MHz
800 MHz
1000 MHz
Texture Fillrate
102.5 Gtex/s
102.5 Gtex/s49.4 Gtex/s89.6 Gtex/s
80 Gtex/s
Memory Clock
1502 MHz
1502 MHz1002 MHz
1250 MHz
1200 MHz
Memory Bus
256-bit
192-bit
384-bit384-bit
256-bit
Memory Bandwidth192.2 GB/s
144.2 GB/s
192.4 GB/s240 GB/s
153.6 GB/s
Graphics RAM
2 GB GDDR5
2 GB GDDR51.5 GB GDDR5
3 GB GDDR5
2 GB GDDR5
Die Size
294 mm2
294 mm2520 mm2365 mm2
212 mm2
Transistors (Billion)
3.54
3.543
4.31
2.8
Process Technology
28 nm
28 nm40 nm
28 nm
28 nm
Power Connectors
2 x 6-pin
2 x 6-pin1 x 6-pin,
1 x 8-pin
2 x 6-pin
2 x 6-pin
Maximum Power
170 W
150 W
244
200 W
175 W
Price
£330
£250N/A
£300
£250


Nvidia says GeForce GTX 660 Ti will sell for around £250, putting it up against AMD's Radeon HD 7870. The GTX 660 Ti might suffer a narrower memory interface, but its fast 1502 MHz memory plays an important role in maintaining competitive levels of bandwidth. Pixel fillrate is lower on the new GeForce card, though.

According to Nvidia, it expects the GTX 660 Ti to beat AMD's Radeon HD 7870, and even compete against Radeon HD 7950 (even though the Tahiti GPU-based Radeon wields notably more memory bandwidth). 

In an attempt to sweeten the launch, Nvidia's partners should be bundling a coupon for Borderlands 2 with GeForce GTX 660 Ti cards.

MSI GeForce GTX 660 Ti Power Edition

There isn't a reference version of GeForce GTX 660 Ti. So, MSI sent over two of its GeForce GTX 660 Ti Power Edition boards for testing single-GPU- and SLI-based performance.

MSI’s interpretation of the GeForce GTX 660 Ti is a little more expensive than what Nvidia told us to expect. It sells for £260 on Scan. The extra money pays for a faster 1019 MHz base clock (typically able to boost to 1097 MHz), an aftermarket Twin Frozr IV cooler, what MSI markets as its military-class components, and control over three voltage levels (GPU, memory, and VDDCI).

As expected, we see the same output options as Nvidia's reference GeForce GTX 670: two dual-link DVI connectors (one DVI-I and one DVI-D), a single HDMI port, and one DisplayPort output. The card can handle up to four screens in desktop mode, three in Surround mode, and a 3x1 + 1 combination (three monitors in Surround mode and the fourth in desktop mode). And, unlike most of AMD's Radeon cards, utilizing DisplayPort isn't a requirement for gaming across three panels.

The card’s PCB measures 9.5” x 4.5”, which is the same as Nvidia's reference specification and identical to the similarly-priced Radeon HD 7870. Two six-pin auxiliary power connectors combine to deliver the 190 W specified by MSI. That's 40 W higher than Nvidia's specification, and likely a result of more aggressive factory overclocking. Nvidia points out that, if you forget to attach those power leads, the card will boot to a warning screen.

MSI’s Twin Frozr IV cooler consists of a four-heat pipe system with two 80 mm fans. Company representatives claim that its design discourages dust build-up, though we can't speak to that specifically, given limited testing time. We can, however, confirm that the card is quiet and cool-running, which we'll quantify in our thermal and acoustic testing.

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  • 0 Hide
    HEXiT , 16 August 2012 23:09
    pretty much as i have been saying for a few months now. 580 or better perfomance for 580 prices from the 660ti
    glad to see the drop in bitrate didnt have such a marked performance hit that it has in the past when they limited other cards this way.
  • 0 Hide
    mi1ez , 17 August 2012 00:15
    Pity about the memory bandwidth. I think I'd stump up the extra £40 or so for the 670
  • 0 Hide
    jemm , 17 August 2012 01:59
    I liked its cooling solution, 2x fun looks really good.
  • 2 Hide
    bemused_fred , 17 August 2012 02:05
    Currently, the 7870 looks like a more attractive buy. The card (both the reference and the sapphire overclocked version) are about £220 on amazon, compared to the £250 660ti. Nvidia's going to have to do something about that.
  • 3 Hide
    bah_humbug76 , 18 August 2012 09:19
    Absolutely no regrets about buying the 7870 for £230 a month ago. Sorry Nvidia. Not impressed at all.
  • 1 Hide
    Anonymous , 21 August 2012 05:37
    7870 is the way to go. Higher min frames (the other review sites used ridiculously fast cpus to mask the 660ti's inferior min frames. Once you crank up the settings the 660ti falters because of gimped memory bus. HD7000 cards in general have better tesselation, antialiasing performance and not to mention compute. They are priced better too. AMD released a much more balanced architecture instead of solely focusing in pixel-pushing performance. GCN cards have the superior architecture overall.