ASUS has its own way of putting a special spin on its GPU offerings through special overclock models along with DirectCU II cooling solutions which always tend to deliver something special. Today we have an ASUS GeForce GTX 660 on the test bench to see exactly how this bang for the buck card will perform.[review_ad]
Introduction – ASUS GeForce GTX 660 DirectCU II
The ASUS GeForce GTX 660 DirectCU II edition is a reference clocked GPU with a single 6 Pin PCIe power connector and it supports up to 2-Way SLI, but that is where the similarities end. It is rare to see ASUS stick with a reference design board, especially because their graphics cards come with full SAP components to ensure massive power delivery capability which ensures that overclocks should be much easier and more stable even on a standard clock model. Also the card is fitted with a DirectCU II cooler to ensure that when gaming on an overclocked GPU and VRM, that temps should never be a concern.
The ASUS GeForce GTX 660 DirectCU II comes in three flavors from the standard DirectCU II model all the way to OC and TOP, which share very similar components but the OC and TOP have higher screened GPUs to offer a guarantee clock of a much higher frequency. The card we have today is a reference clocked model and it hits the market at $234.99 directly from Newegg, which is right in the ballpark of all of the other cards of the same make, which means with some of the added benefits already listed this could be one heck of a value.
SAP (Super Alloy Power)
ASUS has great pride in the components they infuse into their graphics offerings, very much like the motherboards we have covered previously. ASUS has what’s called a SAP or Super Alloy Power, which covers the components in the very VRM we are discussing. The components are hand picked for quality and performance based around not only power delivery but efficiency as well. The components in the SAP solution are super durable for a rated lifespan of up to 2.5x what reference cards would offer and also with the DIGI+ controller, your talking ultimate precision which means better voltage stability, better overclocking potential and overall better power efficiency clock for clock.
Here we see a comparison from a reference model GTX 660, which utilizes a 4 Phase analog design VRM with a single POSCAP in place. The DIGI+ version is a 6 Phase design with 3 POSCAPs to ensure no shortage of power or no conceivable way the GPU or components could be left wanting more under a heavy load situation. The Digital controller is one thing that many neglect to look at and with such control it is worth noting that there is no compromise for voltage accuracy and also efficiency as components are much more tightly regulated to ensure a solid and efficient VRM.
Here we see a short detailing of the SAP components and some short informational quips about how they help make for a better card. One thing here is that this is only the surface of what it is truly, as the SAP solution is a complete package of all of these components designed to work together giving not just higher power delivery than reference but also better voltage accuracy and efficiency through the digital voltage control and component selection and design.
Here we have some good detailing directly from ASUS, showing the improvement of the SAP choke component and how it is superior to other designs implemented presently. Other model chokes can make a whine or screeching sound due to the coil vibration, something we’re sure many enthusiasts and overclockers have heard before. The ASUS design has a sealed/filled core to inhibit vibration, which means noise free operation under extreme loading conditions. Another thing to remember is movement makes heat and friction, so less movement will mean cooler running components.
Here ASUS shows off its SAP selection for MOSFET components. These are designed to not only be more efficient but also have a higher power handling capability, which allows them to have extra head room for overclocking, should you really want to push the limit. Also note, the small package design of the SAP component as it is much smaller than the standard or generic MOSFET used on some standard or reference model cards. This allows for a larger VRM design to fit into a smaller space so that you can pack more punch without effecting the tight real estate within the chassis.
The SAP Solid state cap selection are Japanese units with a much higher MTBF than what you may see on other designs. These units are designed to have a very high expected lifetime, which allows users to rest assured that in their gaming rig with these components should have a nice happy life with a very low chance of failure for quite a long time (up to 2.5x as longer than competing components). For those of us that like to throttle our cards and really put the squeeze on them, this means we have the capability built in as the components are solid and reliable and ready to take a pounding.
Here on the rear of the GPU you see dual POSCAPs placed directly on the opposite end of the GPU, which is perfect placement for direct GPU access should it hit a losing spike. When such a spike hits these units help keep stable and reliable power delivery flowing no matter the loading condition.
Here we see what makes the difference for the DIGI+ solution which has to do with the accuracy and efficiency of the Digital controller in comparison to the analog VRM control we see on many other solutions. This level of control allows for unprecedented voltage accuracy, along with lower signal noise and overall more overclockability due to the tighter stability offered by the DIGI+ digital controller.
DCII (Direct CU II)
ASUS DirectCU II coolers are the ASUS way of saying maximum cooling and plenty of quiet with one naming scheme. DirectCU II coolers are direct touch heatpipes to the GPU surface, ensuring the heat is wicked away from the GPU and up into the cooling fin array as quickly as possible. From there, the custom shrouded dual fans push air through the fins effectively but most important quietly to keep the GPU as cool as possible so hopefully it will never hit a temp to need a higher or noisier fan speed. The air pushing through the fin array also helps cool board components and the VRM as well, which is a nice little added bonus to this style cooler since we all know cooler components tend to run stronger, longer and with better efficiency.
AS you see above the heatpipes on this cooler are massive and they are configured in such a way that they maximize the cooling efficiency of the fan airflow from the DirectCU II Cooler.
Here we see that when compared to a reference model cooler the DirectCU II cooler can keep the card up to 18 degrees C cooler which means of course a cooler internal chassis temperature and also better component life expectancy.
Here we can see that the DirectCU II cooler design with its dual fans is actually up to 5dB quieter than a reference design which is huge because dB unlike most measurements is huge steps for each dB in perceived loudness. So to see a 5dB drop is the difference between standing next to a bus and the bus being across a 4 lane street.
Dust proof Fan Technology
You would think that by now everyone would know that one of the number one killer of a fan is the dirt and dust it comes into contact with. Many fans simply are not sealed in such a way that it can keep dust out and in many cases they are not sealed at all, and you can see the sensitive winding area clearly exposed just by looking at the gap.
Here you can see that the ASUS solution is not just sealing the hub from dust but having 2 levels of sealing which means that over the lifespan of the cooler you can expect a much lower likelihood that you will get the grinding or simply the failing that you normally get from the unprotected fan as seen above.
We cannot count how many times we have had a perfectly good card or cooler just to have it become useless because the fan died.
ASUS offers its own software utility and its functionality has grown with generations just like the cards it supports. Of course the card can be overclocked but also voltages can be tweaked and within the GPU Tweak app, we can even launch the GPU info utility which is a full custom version of GPUz. This is a really cool feature and a benefit especially to benchmarkers, who we can definitely see using this card with some of the awesome tweaks we will discuss in the card overview.
There are many tools within the GPU Tweak menus some a little more hidden than others. First off directly form the GPU Tweak utility itself you can check for BIOS updates and even update from within the program. For anyone who’s ever updated a vBIOS before knows that having a tool that can do this in a mere few clicks is really handy.
The charts besides offering real time monitoring can also be setup to log thermals, voltages and clocks so that after benchmark or gaming runs you can see if there was any thermal issues or throttling that may have affected performance.
Nvidia implemented the GPU Boost feature on the new Nvidia GeForce 6 series GPU’s of the Kepler Architecture. This allows the card to have a base clock and it adjusts dynamically or overclocks to a speed of up to a certain amount depending upon the thermal and power envelope. This makes Overclocking these cards a bit different as you now are overclocking with a boost clock and by offsets from the out of the box clocks. We will discuss more of the overclocking aspects in the overclocking section but it does need to be noted. The voltage envelope can be adjusted as well with another offset setting. This will raise the ceiling in most cases for more overclocking headroom pending temps are within check which with this cooler should not be much of an issue.
Nvidia also included another feature as of recent called “Adaptive V-Sync” which allows for better performance while also stutter free gameplay by actively enabling and disabling V-Sync depending upon gaming situation and FPS all without any intervention from the user.
PCI-E Power LEDs
One really cool feature is that there are status LED’s on each PCI-E connector and these help you recognize that power is actively being sent to each connector of the card. (Note: picture is for reference purposes only as the care reviewed today employs only a single PCIe connector and single red and green LEDs)
The dual greens seen above indicate everything is working well. However if the PCI-E cable is not active or is not installed at all, it will give you the red light which tells you something is wrong. We could definitely see some value in this when diagnosing multi card setups or even single card issues. A dead PCI-E power cable could cause you to pull your hair out without these kinds of indicators.
PCI Express Gen 3 Capable
ASUS wants to ensure everyone is aware that PCI-E 3.0 is here and ASUS is ready with not only cards such as this but boards to support it as well.
Overview of the ASUS GeForce GTX 660 DirectCU II
This packaging is something I have seen on many cards now from the GTX600 series lineup. The gray metallic looking finish with tearing claw marks represents something powerful inside trying to claw its way out. This may actually be the perfect representation for this card as it is a decent mid range performance model that looks to have some real promise at a good value. The front is similar to what I have seen before with some simple wordage covering a few key features and a small breakdown image of the DirectCU II thermal design. The rear covers many details about specifications, including an IO shot showing the connectivity of the card and what features it supports. Also included here are some key words about the SAP DIGI+ solution and even the GPU Tweak utility.
Upon opening the box I find the card packaged much like the GTX 660 Ti model I covered previously which folds up and is held in place with a tight plastic wrap once the cardboard surround is folded correctly.
Here is what you get once you remove the GPU and foam and expose the accessories section.
- Installation Disc
- Instruction Manual
- DVI>VGA Adapter
The accessory package is basic and covers connection to pretty much anything from legacy to newer displays. One thing to note is that there is no included power adapter but with the cards single 6 pin most modern PSUs have at least one PCIe 6 pin cable.
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Here is the card unboxed and ready to shine. it is a dual slot design which means that it will fit in most all motherboards without worry of multi card fitment or any other issues. The top shows off triple heat pipes protruding through emphasizing that this cooler means business. The dual fans work in tandem to ensure that things stay nice and cool and operate in such a way that you can barely hear them if at all even under load.
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Here we see the thin profile of the card, it is a nice relief to see a dual slot card again as I got so used to all of the triple slot cards out there that I forget how much easier it can be to work with and around a card that is slimmer dual slot profile. This is nice because it allows better fitment in some cases and motherboards which may have limited space especially such as mATX variants where you may want a SLI setup but can only fit dual slot cards.
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The I/O side has enough connectors to allow for the full 4 displays as supported with the following connections:
Popping the Top
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The heatsink comes off easily as it is held on with 4 screw surrounding the GPU. once removed the GPU and VRM is exposed for our viewing. The VRM and layout looks pretty standard from what I have seen before especially on ASUS cards with the all SAP components which make for a clean and neat looking but powerful VRM.
The cooler has 3 heatpipes all coming across the GPU directly to allow fast pickup of heat and quick transfer to the cooling fin array for maximum cooling capability of the GPU. Also notice that the fin array is not extremely dense which allows for more free airflow which helps reduce fan noise along with allowing cool air to reach the VRM easily keeping things nice and cool.
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Here you can see the VRM components neatly laid out and ready for some extreme loading. This may be a standard clock card but it still carries the same VRM components just minus the higher screened GPU so it is built and ready for some overclocking and heavy loading action.
The DIGI+ controller we are all familiar with and it allows full precise digital VRM control. Besides being precise the DIGI+ controller also offers very efficient operation which allows for much cooler operating performance, along with heavier loading conditions with better performance.
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The power being fed to the card is simple with a single 6 pin which means even some of the most basic supplies will have no issue feeding this card and also means this card is quite efficient for the performance you get.
The card employs a single SLI connector for up to 2 Way SLI unlike the Ti Version which can support up to 3 Way SLI. For most games and gamers this should still make for a very potent setup.
Testing & Methodology
We’ve expanded our testing suite considerably since the X79 chipset release, and will continue to use the same methods for most of the motherboards and CPU’s we test. In the interests of thoroughness and accurate results, we run each test at least three times, and some tests more than that. We average the total of all the tests from each benchmark then report the average here.
The OS we use is Windows 7 Pro 64bit with all patches and updates applied. We also use the latest drivers available for the motherboard and any devices attached to the computer. We do not disable background tasks or tweak the OS or system in any way. We turn off drive indexing and daily defragging. We also turn off Prefetch and Superfetch. This is not an attempt to produce bigger benchmark numbers. Drive indexing and defragging can interfere with testing and produce confusing numbers. If a test were to be run while a drive was being indexed or defragged, and then the same test was later run when these processes were off, the two results would be contradictory and erroneous. As we cannot control when defragging and indexing occur precisely enough to guarantee that they won’t interfere with testing, we opt to disable the features entirely.
Prefetch tries to predict what users will load the next time they boot the machine by caching the relevant files and storing them for later use. We want to learn how the program runs without any of the files being cached, and we disable it so that each test run we do not have to clear Prefetch to get accurate numbers. Lastly we disable Superfetch. Superfetch loads often-used programs into the memory. It is one of the reasons that Windows occupies so much memory. Vista fills the memory in an attempt to predict what users will load. Having one test run with files cached, and another test run with the files un-cached would result in inaccurate numbers. Again, since we can’t control its timings so precisely, it we turn it off. Because these four features can potentially interfere with benchmarking, and and are out of our control, we disable them. We do not disable anything else.
We are revamping our testing method in order to better represent motherboard performance and offering to the consumer. Also we want to make it an easier read for you without miles of endless charts. We ask that you provide feedback in an effort to help us deliver better reviews for you.
|Case||Thermaltake Level 10 GT|
|CPU||Intel Core i7-3770K|
|Motherboard||ASUS Maximus V Gene
|Ram||16GbpsB Patriot Viper Xtreme 2400MHz +|
|CPU Cooler||Swiftech H20-220 Edge|
|Hard Drive||Western Digital Velociraptor 300GB|
|SSD||Intel 510 series SATA III 120GB|
|GPU||ASUS GeForce GTX 660 DirectCU II|
|PSU||Thermaltake Toughpower XT 1275W Platinum|
|Mouse||Tt eSPORTS Black gaming mouse|
|Keyboard||Tt eSPORTS Meka G1 mechanical gaming keyboard|
We will use the following applications to test the performance of the graphics card.
Synthetic Benchmarks & Games
|Heaven Benchmark 3.0|
|Batman: Arkham City|
|Just Cause 2|
|Lost Planet 2|
The ASUS GeForce GTX 660 DirectCU II cooler and SAP components combine every time to make for a great overclocking experience. This is no different with the GTX 660 as the slider keeps moving to a final stable clock of 1135MHz which is quite good at about 15% overclock.
The memory was similar as default is already past 6GHz frequency but the card easily clocked past 6800MHz to a final stable frequency of 6840MHz which is a sizable 13% overclock.
These overclocks are completely stable across game testing and benchmarks and while the card may pull a little further for short benchmark runs this is the max we could get to be considered fully stable. This could easily enable a few extra frames and give a much smoother gameplay for a gamer who might have been on the edge previously. This and the fact that I’ve never been one to complain about free performance so i’m not gonna start now.
|Clock||Stock Frequency|| Max stable MHz
|GPU Base clock||980MHz||1135MHz||15%|
|Memory clock||1502MHz (6008MHz)||1710MHz (6840MHz)||13%|
In order to ensure no system bottleneck we clocked the CPU to 4.6GHz to ensure there is no reason the system will slow down the cards performance at all.
Some may ask why we chose the mainstream Z77 system, and we can explain. Up until recent the X79 enthusiasts platform did not really support PCI-E Gen 3 on the Nvidia 600 series GPU’s. Because of the inherent instability many have seen with the X79 platform with Gen 3 products, Nvidia has been hesitant to enable it, and now there is a workaround via registry to get it working. However, in order to ensure the most consistent testing possible, we have stuck to the natively supported Z77 platform.
Important note: Overclocking can cause component failure. Please exercise caution when attempting any level of overclock on system components.
The temperatures were recorded with full loaded Heaven benchmark looping for over 30 minutes or longer depending how long it took for the card to level out in temps and sat at a plateau for more than 10 minutes.
|GPU Temperatures||Temperature (Idle/Load)|
|ASUS GeForce GTX 660 DirectCU II OC||31C/65C|
|ASUS GeForce GTX 660 DirectCU II||31C/63C|
The DirectCU II cooler worked excellently as the fans stayed nice and quiet throughout the runs and even when overclocked it swallowed up the heat and kep chugging along without issue.
Real world/Gaming Benchmarks
3DMark 11 is the newest in Futuremark’s suite of benchmarking utilities. Its a fully capable DirectX11 benchmark which also stresses and analyzes the system performance as a whole to simulate a heavy rendering environment such as a high end game or other app the end user may run. This benchmark was run with Performance settings 5 times and all runs were averaged for the result below.
3DMark 11 shows a nice picture of where each card falls in line coming from our testbench. The GTX 660 DCII falls right in line above the 650 Ti and below the 580 in the performance preset. The extreme preset lets the 660 DCII’s 2GB of frame buffer shine as it pulls ahead of the 1.5GB 580 and further distances itself ahead of the 650 Ti.
Unigine Heaven 3.0
Unigine Heaven is a benchmark program based on Unigine Corp’s latest engine, Unigine. The engine features DirectX 11, Hardware tessellation, DirectCompute, and Shader Model 5.0. All of these new technologies combined with the ability to run each card through the same exact test means this benchmark should be in our arsenal for a long time.
Here we see once again the 660 DCII jumping ahead of both the GTX 560 and 650 Ti and nothing in just on the heels of the 580 which is not a bad place to be as this card is roughly half the price of the 580 at launch.
Metro 2033 has always been extraordinarily stressful for GPU’s, and this has not changed with time. Here you can see the ASUS 660 offering actually creeping very close to the EVGA SC card by just a a frame at 1680×1050 and even less at 1080P which is not bad at all and I can imagine with the overclock the ASUS card could easily jump up even more.
Lost Planet 2
Lost Planet 2 shows a definite trend here as the 660 DCII hangs right in position just nipping at the heels of the previous gen flagship 580 and well ahead of one of AMDs premier performers the 7950! This little 660 is proving to be a real winner in teh price for performance category.
Batman: Arkham City
We tested Batman Arkham City and once again the 660 DCII finds itself in a power position actually beating out the 580 by a decent margin with over 15 FPS difference and that is quite alot for a card of this pricing and position.
Just Cause 2
I just had to test Just cause 2 as it is an awesome game with some very good visuals. The 660 pulls off a respectable performance but this time it falls a bit behind the 580 and even the previous gen 560 Ti as it seems this game is very friendly to the older architecture. But even with this considered the 660 pulls of a nice showing with very playable frame rates in excess of 60 FPS average which means it should be nice and smooth.
Dirt 3 is a great game for visuals and yet pulls very reasonable framerates on most cards so the 660 DCII pulls over 60 easily. and beats out the 560 Ti this go around but is at the heels of the 7950 and 580 this time. This is not bad company to have as these are top level GPUs and that means this is one excellent performer.
The ASUS GeForce GTX 660 DirectCU II is a surprising and powerful card. At less than 250 bucks, you get a card that is right at the heels of the GTX580 in most scenarios. This card has a very low power requirement with its single 6 pin PCIe connector and even smaller thermal dump with the help of the DirectCU II cooler. The SAP powered VRM makes for an amazingly efficient and very overclockable and stable card as well.
The performance is very good and the size of the card means it should fit in most smaller cases including most LANBOX style chassis. The card runs and runs well, there is little else I can say besides it simply handles business in the gaming department and even supports PhysX for more in-depth gaming. If needed for processing CUDA apps are fully supported as well.
The GPU Tweak app helps to unlock the full potential of the card quickly and easily with easy and intuitive interface.
Anyone looking for a strong mid-range performance card that can really punch out some gaming performance at a decent price point, I find no reason why the ASUS GeForce GTX 660 DirectCU II would not make your list of considerations.
|OUR VERDICT: ASUS GTX 660 DirectCU II|
|Summary: The ASUS GeForce GTX 660 DirectCU II hits a price/performance ratio and a power/performance ratio that is tough to beat. For this it receives the Bjorn3D Golden Bear Award.|