The GeForce GTX 660 Ti Review, Feat. EVGA, Zotac, and Gigabyte
by Ryan Smith on August 16, 2012 9:00 AM ESTCompute Performance
Shifting gears, as always our final set of real-world benchmarks is a look at compute performance. As we have seen with GTX 680 and GTX 670, GK104 appears to be significantly less balanced between rendering and compute performance than GF110 or GF114 were, and as a result compute performance suffers. Cache and register file pressure in particular seem to give GK104 grief, which means that GK104 can still do well in certain scenarios, but falls well short in others. For GTX 660 Ti in particular, this is going to be a battle between the importance of shader performance – something it has just as much of as the GTX 670 – and cache/memory pressure from losing that ROP cluster and cache.
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.
For Civilization V memory bandwidth and cache are clearly more important than raw compute performance in this test. Although this isn’t a worst case scenario outcome for the GTX 660 Ti, it drops substantially from the GTX 670. As a result its compute performance is barely better than the GTX 560 Ti, which wasn’t a strong performer at compute in the first place.
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.
Ray tracing likes memory bandwidth and cache, which means another tough run for the GTX 660 Ti. In fact it’s now slower than the GTX 560 Ti. Compared to the 7950 this isn’t even a contest. GK104 is generally bad at compute, and GTX 660 Ti is turning out to be especially bad.
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 GTX 660 Ti does finally turn things around on our AES benchmark, thanks to the fact that it generally favors NVIDIA. At the same time the gap between the GTX 670 and GTX 660 Ti is virtually non-existent.
Our fourth benchmark is once again looking at compute shader performance, this time through the Fluid simulation sample in the DirectX SDK. This program simulates the motion and interactions of a 16k particle fluid using a compute shader, with a choice of several different algorithms. In this case we’re using an (O)n^2 nearest neighbor method that is optimized by using shared memory to cache data.
The compute shader fluid simulation provides the GTX 660 Ti another bit of reprieve, although like other GK104 cards it’s still relatively weak. Here it’s virtually tied with the GTX 670 so it’s clear that it isn’t being impacted by cache or memory bandwidth losses, but it needs about 10% more to catch the 7950.
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 GK104. 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.
Interestingly Folding @ Home proves to be rather insensitive to the differences between the GTX 670 and GTX 660 Ti, which is not what we would have expected. The GTX 660 Ti isn’t doing all that much better than the GTX 570, once more reflecting that GK104 is generally struggling with compute performance, but it’s not a bad result.
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TheJian - Sunday, August 19, 2012 - link
You forgot to mention the extra heat, noise and watts it takes to do that 1250mhz. Catching NV's cards isn't free in any of these regards as the 7950 BOOST edition already shows vs. even the zotac Amp version of the 660ti.AMD fanboys might call these features these days I guess...
Galidou - Monday, August 20, 2012 - link
7950 boost is a reference board, as we said before, 4 out of 18 boards are reference on newegg. It's unlikely people will buy reference cooler from AMD because they're plain bad if you overclock. Will people putting the reference design out of the way when speaking about overclock....Noise and temperature when overclocked on either for example Twin Frozr3 from MSI or sapphire OC are ALOT more silent and cool even fully overclocked....
TheJian - Monday, August 20, 2012 - link
Nearly every card on newegg is OC'd by manufacturer and the top listed boost isn't even the top it can do by default which os a Nice.CeriseCogburn - Thursday, August 23, 2012 - link
The GTX 580 was already way ahead, so it didn't have to catch up to 6970. When OC'ed it was so far ahead it was ridiculous.That's why all the amd fans had a hissy fit when the 680 came out - it won on power - frames, features, price - all they could whine about was it wasn't "greatly faster" than last gen (finally admitting of course the 580 STOMPED the pedal to the floor, held it there, and blew the doors off everything before it).
See, these are the types of bias that always rear their ugly little hate filled heads.
Galidou - Thursday, August 23, 2012 - link
''ugly little hate filled heads''The sentence speaks for itself about who's writing it, you're one of them sorry, if it wasn't so filled with hate maybe I could pass but.... no.
It won for the first time on power/performance, let'S not do like it has always been like that.... and before even if they didn't win on that front you speak like they won on everything forever. There's nothing good about AMD we already know your opinion, you don'T have to spread some more hatred on the subject, we know it.
Just do yourself a favor, stop lacking respect to others for something everyone already knows about you, you hate AMD end of the line.
CeriseCogburn - Thursday, August 23, 2012 - link
You were wrong again and made a completely false comparison, and got called on it.Should I just call you blabbering idiot instead of hate filled biased amd fanboy ?
How about NEITHER, and you keeping the facts straight ?
HEY !
That would actually be nice, but you're not nice.
Galidou - Tuesday, August 21, 2012 - link
You didn't get the point of the memory controller/memory quantity they said here, poor newbie, let me explain things for you. On GCN there's 6 64bit memory bus, now divide 3gb of memory into 6, bingo 512mb each controller. Now take 2gb of memory and divide it by 3 memory bus of the 660 ti(192bit), ohhh you can't do this, what that means is there are 2 64 bit buses that takes care of a 512mb chip and the 2 other memory buses take care of 2x512 memory each.Asynchronous memory may not be that bad, it isn't a weirdo theory either, my little girl that's 10 years old would understand it if I would explain her that simple mathematical equation. Mr Cogburn the expert with less logic than a 10 y old girl... what are you doing here, you'Re so good, maybe you should join us at overclock.net and discuss with some pro overclockers and show us your results of your cpu/gpu on nitrogen if you're so pro about hardware.
CeriseCogburn - Thursday, August 23, 2012 - link
Wow, and to think you just said you couldn't support the hatred, but there you go spreading your hatred again.The author is WRONG. Be a man and face the facts.
Galidou - Thursday, August 23, 2012 - link
I didn't use a damn word that lacked of respect to you in all my previous posts unlike you calling me dummy, stupid, and so on in some previous post. You used words nazi, evil, and so on against AMD but I'm the one who spread the HATE LOL COMON.Don't try me, you are the most disrespectful, but still knowledgeable, person I've ever seen at your times. You expect me to stay totally cold all the time in face of the fact you diminish and attack people calling them names because they are Fanboys.... COMON.
I speak once against your logic but every post you have is full of hatred and attack to people but ohhh when I say something ONCE, it's BAD. COMON.... Well I know it wasn't my best one and I offer you my dearest excuses, I truly am sorry. I was at the end of the roll, you're hard to follow, using everything you can to make us feel like AMD is realted to cancer, hell, nazis and such while I have a 4870 and 6850 crossfire that served me well.
Imagine someone attacking and diminishing the user of a product because he uses the said product and you're one owner of that said product. Someone lacking of respect to YOU in every way because you use that thing and you actually like it and it served you well, you had no problem with it but still he can't stop and almost tries to make you beleive that if you bought that, it'S because you are plain stupid. You'd be mad, well that's what you make feel to most of AMD users the way you speak of them.
I'm sorry for being such an ass comparing your logic to my 10 years old daughter while I know you're more logical than her. But you should really be sorry to any AMD video card owner that reads you because you really make em beleive AMD is the devil and their products are worthless while they're not.
CeriseCogburn - Thursday, August 23, 2012 - link
Don't start out with a big lie, and you won't hear from me in the way you don't like to hear or see.You've got yourself convinced, you already did your research, you've said so, you've told yourself a pile of lies, WELL KEEP YOUR LIES TO YOURSELF THEN, in your own head, swirling around, instead of laying them on here then making up every excuse when you get called on them !
Pretty simple dude.
Here' let me help you, this is you talking:
" I've been brainwashed at overclockers and all the amd fanboys there have convinced me to "get into OC" and told me a dozen lies, half of which I blindly and unthinkingly repeated here as I attacked the guy who knew what he was talking about and proved me wrong, again and again. I hate him, and want him to do what I say, not what he does. I want to remain wrong and immensley biased for all the wrong reasons, because being an amd fanboy is my fun no matter how many falsehoods I spew that are very easily smashed by someone, whom I claim, doesn't know a thing after they prove me wrong, again and again".
Hey dude, be an amd fanboy, just don't spew out those completely incorrect falsehoods, that's all. Not that hard is it ?
LOL
Yeah, it's really, really hard not to, otherwise, you'd have a heckuva time having a single point.
I get it. I expect it from you people. You've got no other recourse.
Honestly it would be better to just say I like AMD and I'm getting it because I like AMD and I don't care about anything but that.