Review Index:

NVIDIA GeForce GTX 660 Ti Overclocked Roundup - EVGA, Galaxy, MSI and Zotac

Author: Ryan Shrout
Manufacturer: Various

Overclocking Results

Let's get this out of the way up front here: the overclocking results on this page are but a single data point in a wide array of parts that will be available on the market.  While we might get GREAT results from a particular GPU, that doesn't mean you are going to get the same results when you buy yours or even that vendor A will overclock further than vendor B if you were to buy the same cards we used here.  That's just the nature of the game – we just play by its rules.

For our testing here, we used EVGA's Precision X software though you could have (as we verified) used MSI's Afterburner or Galaxy's Xtreme Tuner and access the same features, the same knobs, and the same results. 

If you need a quick refresher on how the Kepler GPU overclocks you should read over this page of our GeForce GTX 680 review but here is the highlight:

The GPU clock offset is the other adjustable factor and it actually moves the entire performance curve up.  Think of it this way: when you set an offset of 50 MHz you are telling the GPU that its new base clock is 1056 MHz rather than 1006 MHz, and all the GPU Boosting is based off of that new base rate.  It is still possible to overclock your GPU too far and crash the system (as I did several times) but I think that is a good thing for consumers that want to make sure they are hitting the limits of their hardware.

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We connected a second monitor to keep the EVGA Precision X software and monitoring window open while testing and running games, and in the end we decided that our "stable" platform was going to be set by being able to complete a run of the very GPU intensive Unigine Heaven benchmark.  I found that this benchmark was much more "unstable" when it came to high offsets, and therefore gave us a worst-case scenario for long-term game playing sessions. 

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As you might remember, two of the more important numbers for GeForce GTX 660 Ti overclocking are the power % and the GPU clock rate.  The Power % indicates how much of the card's TDP is being utilized, and a number over 100% means we are pushing more than the 150 watt number that NVIDIA set as the TDP.  Both the Power % and the clock rate will vary in real time as the game state changes.

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For our comparison testing, we set the Power Target on all four cards to their highest setting. It was 123-125% for the Galaxy, EVGA and Zotac cards but only 14% for the MSI card!  Try as we might, we couldn't get around that level in either EVGA's or MSI's own overclocking software.  This is more than likely holding up the MSI card's overclocking ability, and hopefully they'll have an answer for us soon.

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Here you can see our maximum stable GPU clock speed for each card. Keep in mind that, as I mentioned above, your mileage will likely vary.  Keep in mind as well that these are total clock speeds, not JUST the offset.  For example, while the Zotac card hit the highest base clock speed with a 1093 MHz rate, the EVGA had the highest offset with a 70 MHz (versus 60 MHz on the Zotac). 

Also note that even though the Boost clocks are only going as high as 1171 MHz, those are the "normal" Boost clocks; as you can see in our image above we were able to hit over 1250 MHz clock speeds during our benchmarking and gaming tests.  In fact, the Zotac AMP! Edition was able to stay steady at 1275 MHz with a +60 MHz offset, the EVGA SC would run at 1266 MHz, Galaxy's GC card could run at 1189 MHz without issue, and MSI was able to clock to 1176 MHz. 

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How did our temperatures change once we threw in some overclocking?  Actually, not by much. With the Zotac and EVGA solutions both increasing by 4C, the MSI cooler by a single degree, and the Galaxy cooler remained unchanged.  I should note here as well that sound levels for all four cards remained basically unchanged, moving only a 0.1-0.2 of a dB. 

I did attempt to use the EVGA software to push the voltage up to the maximum of 1.175v, but the cards were already nearly hitting that voltage by just adjusting the power target and offset sliders so we didn't see any additional headroom in that.  When we get the MSI software working to increase the voltage beyond that, we may come back here for a second look.

What does it all mean for those of you looking to overclock?  Honestly, I think all of these cards are going to do pretty well but the Zotac, MSI and Galaxy cards really stand out for having a much better cooling solution than the EVGA SC model.  The Zotac AMP! GeForce GTX 660 Ti was able to hit the highest clock speed in my testing, but even the MSI card with its 114% power target bug was within ~40 MHz. 

August 29, 2012 | 12:45 PM - Posted by jtiger102

Is there any reason to think that the stock version of these cards couldn't overclock to the level of the OC cards?
For example, the regular ZOTAC card looks to have the same cooler and configuration otherwise.

August 29, 2012 | 01:29 PM - Posted by Ryan Shrout

No, not really, they likely could.  Just a matter of what you want out of the box really.  The one thing you should watch for is the cooler and power configuration.

August 29, 2012 | 01:43 PM - Posted by Pimpsmurf (not verified)

Ryan could you tell us what the idle temps were for these cards? Just to see comparison/jump to load temps.

August 29, 2012 | 02:08 PM - Posted by Ryan Shrout

Sure, I'll try to get these for you.

August 29, 2012 | 01:51 PM - Posted by Yeno (not verified)

Correct me if I'm wrong Ryan, but don't these benchmarks basically show that the 660 ti is somewhat bottle necked by the memory bandwidth?

August 29, 2012 | 02:08 PM - Posted by Ryan Shrout

Correct.  And we thought as much with the drop to a 192-bit memory bus width.

August 29, 2012 | 02:19 PM - Posted by mark (not verified)

Honestly knowing the memory situation, I recommend the card with the highest quality memory that can be overclocked because that alone is the performance boost for this card....I swear I read a review of a 660ti with some special memory chips...I dunno

August 29, 2012 | 02:26 PM - Posted by Ryan Shrout

Haven't seen any like that yet...

August 29, 2012 | 02:20 PM - Posted by mark (not verified)

Oh yea and Kudos to Zotec with the shorter card! Good for smaller cases.

August 29, 2012 | 02:48 PM - Posted by krvi (not verified)

I ordered the Zotac card early (19th) since I have an SFF system and the Zotac card would be the only one to fit it.
I havent recieved it yet, but thank you for reassuring me that it was a good choise.
I have seen some sites claiming that zotac has a GTX 660 Ti Extreme edition in the making. While some say this is only intended for the chinese market, do you have any info on this and perhaps more specifics, like the size, of that card?

August 29, 2012 | 04:18 PM - Posted by Ryan Shrout

Haven't heard anything yet, sorry.

August 29, 2012 | 04:39 PM - Posted by Thedarklord

Great read Ryan.

It is interesting to see just how much Kepler is affected by memory bandwidth and memory type.

Though we are seeing the downsides to GK104 being spread out as a entire product range, since GK104 was "meant" to be mid-range from the start. While the GTX 680/690/670/660 TI are great cards, they still dont target the "sweet spot" in my opinion, which is in the $150 - $250 ranges (aka cards like GTX 460/560 TI/ect).

#Side note: Do you need any more good reviewers/podcasters ;), lol.

August 30, 2012 | 01:33 AM - Posted by jakman220 (not verified)

I was able to overcloxk a stock 660 ti to within 10% of the speed and bandwidth of a GTX 670, which is realy great imho. The temps were below 75*C.

August 30, 2012 | 01:51 AM - Posted by jakman220 (not verified)

Yup I got my O.C. to 1038/1103/1815 w/a temp at 78*C max.

August 30, 2012 | 02:00 AM - Posted by jakman220 (not verified)

The card is a EVGA 660ti. Overclock the memory and you can overcome the bandwidth restriction. Then the $299 card becomes a real value especialy w/the Borderlands game included.

August 30, 2012 | 11:18 AM - Posted by Ryan Shrout

Agreed, the $50-60 value of the game is pretty enticing considering it is just a current and big name title.

August 30, 2012 | 01:07 PM - Posted by Anonymous (not verified)

It will be interesting to hear MSI's reason for the 114% Power cap. Could it be intentional to keep the Power Edition 660 Ti from overclocking as high as the more expensive Lightening edition?

September 7, 2012 | 08:24 PM - Posted by Sixlef (not verified)

The gpu temperatures dont are rigthes

i have a msi 660 ti oc and my gpu temperatues all all times higths thand yours .

September 16, 2012 | 02:40 AM - Posted by Anonymous (not verified)

got my msi 660ti to 1145/1223 and the memory to 1727mhz resulting in just about 7000mhz with afterburner,3dmark11 standard run P 8735 with those settings P 9237.
pretty good,but the memory bandwith just sucks,metro 2033 on high settings and 4xMsaa and 16xaf i cant get more than 30fps-35fps often dropping below that in intense scenes.
do yourself a favour and spend extra for a gtx 670 as you can run even very high settings and still preform better than a 660ti,and i play only on a 1920x1080 screen.a recent test revealed that even a AMD 7750 performs better with msaa and af settings put to max due to the memory bandwith.

April 3, 2013 | 06:29 PM - Posted by Anonymous (not verified)

I just purchased 2 EVGA GTX 660 TI SC+ 3GB and they are only hitting 60C under load. I'm not sure if something was changed in the 3GB version or if I just have a good card.

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