ASUS GTX 680 2GB Overclocking Review: Win Some Lose Some

[siopao1984]

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After a long and turbulent few months filled with much speculation and deliberate misinformation, we finally have NVIDIA's belated response to the the 28nm AMD Southern Islands GPUs - the Geforce GTX 680 (current name, among former identities). In the first of many Keplers that we will be evaluating, we take a look at ASUS's reference offering and see if its indeed a worthy contender (or pretender) to the reigning king of the hill Radeon HD 7970. Overclocked benchmarks also included!

Introduction and Specifications(ED: Due to the limited amount of time and deliberate obstruction by hostile parties who will remain anonymous, we will review the card as is first and publish a technical piece on the new Nvidia Kepler architecture later today or tomorrow.)Here we have the ASUS GTX 680 2GB, based off NVIDIA's reference design. We won't be too surprised to see custom Direct CU variants later.

Card measures 10 inches long (shorter than HD 7970 @ 11.5 inches) and takes up 2 slots.

NVIDIA deployed a 6+6 pin PCIe connector (theoretically means up to 75+75+75W of power draw) on this board with a new stacked layout. If we look closely on the PCB we can see unused solder points for another 6 pins, implying that there could be other SKUs with higher power requirements.

I/O Panel - We get a full sized DP, HDMI connectors (why not their mini/micro variants?) as well as single-link and dual-link DVI outputs. We are not a fan (get the pun?) of half height exhaust holes as it creates unnecessary turbulance and kills the possibility of single slot water cooling

Back of card - would really prefer a backplate here to prevent short circuits, considering that a lot of vital soldering points are exposed.

This card has got one of the most spartan bundles ever - only a double Molex to 6-pin PCIe convertor and the mandatory manual/driver CD.

By default, the reference cards are clocked just over 1GHz on the core (which is the trend for new cards now, not accounting for fancy GPU Boost throttling) and a commendable 1.5GHz GDDR5 (6GHz) on the memory. With only 2GB of framebuffer and a 256 bit memory bus (as opposed to 3GB and 384 bit on the cards they are competing with), this disparity will come into play in bandwidth starved scenarios like high (ahem multi-monitor) resolutions and scenes with complex textures. Like all the other cards this year, the GTX 680 comes with PCIe 3.0 support which is currently only (unofficially) supported by Intel's enthusiast Sandy Bridge-E and the upcoming Ivy Bridge mainstream chips.

Read more: ASUS GTX 680 2GB Overclocking Review: Win Some Lose Some by VR-Zone.com

[siopao1984]

Useful consumer information no other site will tell you today - for boffins looking to dismantle their cards, you'll need a Torx T6 screwdriver to screw most of the screws.



The GTX 680, stripped naked for your eyes only.



Here we have the GK104 die, which measures 294mm2 and houses 3.5 billion odd transistors - slightly smaller the AMD's Tahiti XT (HD 7970). There is also a metal shim surrounding the die which is of the same height so no grief for custom heatsinks here.



The same 256mb Hynix BGA module GDDR5 used in the 2012 Radeons, somebody's stock must be heading sky high.



3+2 phase power circuitry (less than the 6+2 on the HD7970) for 195W TDP



A software programmable 5-phase Richtek RT8802A buck controller is used (found behind)



Two SLi connectors provide the opportunity for a 4-way dance. No dual bios switch here for consequence-free experimentation



With the platic shroud taken off, we see a vapor chamber and blower design which is typical on high end boards.



On the heatplate itself, there are sticky thermal tape for the VRMs and memory modules. Unfortunately we couldn't reach the centrifugal blower fan as the screws are under the tape which cannot be reapplied easily.



No fancy heatpipes sticking out from the heatsink block (Vapor Chamber), just a copper base and thermal paste.

[siopao1984]

Software

At the time of writing ASUS's GPU Tweak for the GTX 680 wasn't publicly available yet, but we managed to nab a screenshot from the review guide. In this and other similar brand OC utility we have the option to set offset values for the core clocks and voltages as well as a new option called Power Target (like PowerTune on AMD boards) to extend the TDP cap to 137%. As we have covered in other recent ASUS graphics card reviews before, GPU Tweak also comes with FRAPS-like screenshot/video recording features and a live update utility to check for VGA BIOS updates.



Thermals, Power Usage and Overclocking

Methodology: We set the fans to 100% (strangely the sliders will only let us apply 85%) and looped Unigine Heaven 3.0 on extreme settings for 10 minutes and took the maximum temperature from the ondie sensor. Ambient temperature was 18 degrees.



At stock settings, we see some kind of turbo boost bringing the core clock to 1137MHz. At this point temperatures maxed out at 52 degrees celsius and the card used ~180W of power.





After applying a +200MHz core offset overclock (bringing it to an effective l33t MHz) combined with a 100mW voltage boost and TDP cap raised to 137%, we got a maximum of 59 degrees celsius on the core and ~210W of power used.







Test Setup



CPU: Intel Core i7-3960X @ 4817MHz 1.52v
Motherboard: ASUS Rampage IV Extreme (Bios 1103)
Memory: G.Skills ARES 2133Mhz DDR3 16GB Kit
Power Supply: Antec True Quattro Pro 1200W
Storage: Intel 520 series 250GB SSD
Graphics Cards / Drivers:
300.99 drivers:
ASUS Geforce GTX 680

296.10 WHQL drivers:
ASUS GTX580 DirectCU II 1.5GB

8.960 beta drivers:
MSI R7970 Lightning 3GB
AMD Reference Radeon HD 7970 3GB
Sapphire Radeon HD 7950 OC Edition
AMD Reference Radeon HD 7870 2GB
ASUS HD6970 DirectCU II 2GB

[siopao1984]

Benchmarks (Synthetic)

3DMark 11

At 720p resolution, we see the stock GTX 680 holding a 20% lead over the stock HD7970. When they are max overclocked (albeit different clocks), the difference narrows to 9% which shows that the HD 7970 could actually be faster if the clocks are normalized. All the other cards are just spectators in this battle at the top, falling almost 50% behind.





At 1080p, the GTX 680's lead is narrowed to 13% at stock and just 4% overclock for overclock vs the HD 7970. Clearly the lack of memory bandwidth or shader efficiency is telling here, but the GTX 680 is leading nonetheless.





Unigine Heaven 3.0 (DX11)

With tesellation disabled, the extra memory bandwidth and better raw muscle probably helped HD 7970 to keep up with the GTX 680 in this notoriously fillrate heavy benchmark. Both the top dogs are head to head when overclocked while the rest are too asthmatic to keep up.





When tessellation is set to extreme, the GTX 680's superior algorithms puts distance between itself and the HD 7970. Notice the almost 50% drop here for the AMD cards with reference to the above diagram.





LuxMark 2.0

Either there is something wrong with NVIDIA's OpenCL driver implementation or the Kepler floating point units are bonked - the GTX 680 is even behind the old Fermi GTX 580! We see this happening on other OpenCL benchmarks that we've informally tested as well and will follow up with a separate piece on this.





ComputeMark

We see a similar situation here with the compute mystery but this time with DirectX 11, and the results are significant here as they affect ambient occulsion performance in modern titles like DiRT 3 and Battlefield 3 (tested on the next page).





ShaderToyMark 0.20 (OpenGL Pixel Shader Test)

The GTX 680 regains the lead here but not by much. Once the cards are overclocked the HD 7970 surges in front.





SPECviewperf 11 (OpenGL Workstation Tests)

We threw in a workstation benchmark here (OpenGL heavy). No wins for the GTX 680 except in the catia test. Both vendors would pretty much like these type of users to buy Quadros and FireGLs, but not everybody can afford these thousand dollar cards that are essentially the same hardware as consumer grade boards.





Description of application tests (taken from SPEC.org):

The snx-01 viewset is based on traces of the Siemens NX 7 application. The traces represent very large models containing between 11- and 62-million vertices, which are rendered in modes available in Siemens NX 7.

The tcvis-02 viewset is based on traces of the Siemens Teamcenter Visualization Mockup application (also known as VisMockup) used for visual simulation. Models range from 10- to 22-million vertices and incorporate vertex arrays and fixed-function lighting.

The sw-03 viewset was created from traces of the graphics workload generated by the Solidworks 2009 SP2 application from Dassault Systemes.

The proe-05 viewset was created from traces of the graphics workload generated by the Pro/ENGINEER Wildfire™ 5.0 application from PTC. Model sizes range from 7- to 13-million vertices.

The maya-03 viewset was created from traces of the graphics workload generated by the SPECapc for Maya 2009 benchmark.

The ensight-04 viewset represents engineering and scientific visualization workloads created from traces of CEI's EnSight 8.2 application.

The catia-03 viewset was created from traces of the graphics workload generated by the CATIA™ V5 R19 and CATIA V6 R2009 applications from Dassault Systemes.

The lightwave-01 viewset was created from traces of the graphics workloads generated by the SPECapc for Lightwave 9.6 benchmark.

[siopao1984]

Benchmarks (Games)

Alien vs Predator (DX11)

We deliberately used the highest possible settings, as buyers of such cards would do. The lack of memory bandwidth cripples the GTX 680.



Resolution: 1920 x 1080, Texture/Shadow Quality: 3, Anisotropic Filtering: 16, SSAO: ON, Vertical Sync: OFF, DX11 Tessellation/Advanced Shadows: ON, DX11 MSAA Samples: 4





Battlefield 3 (DX11)

Face it - the only reason why gamers would buy a top of the line graphics card today is for Battlefield 3, which is probably the only (fun) game today able to bring systems to their knees. The GTX 680 is 14% faster than the HD 7970 at stock, but things get very, very close when they are both overclocked.









Crysis 2 (DX11)

Don't we just love to troll in the comments section - "Its nice, but can it run crysis?" In this ridiculously tesellation heavy TWIMTBP title (means you get a NVIDIAAAA badge loading sequence when you start the game), the GTX 680 is unsurprisingly 17.5% ahead at stock. Once again, the difference narrows considerably once both cards are overclocked.





Resolution: 1920x1080 Map: Downtown, Quality: Ultra with Hi-res Textures, API: DX11, AA: Off





Left 4 Dead 2 (DirectX 9)

Valve's award winning Source Engine may be dated but it is still notoriously GPU dependent. Either AMD has put in better driver optimization here or well, you know the rest.





Resolution: 1920x1080, AA: 8x MSAA, Filtering Mode: Anisotropic 16X, Vsync: Disabled, Shader: Very High, Effect/Model/Texture/Paged Pool: High, Multicore Rendering: Enabled

[lloyd_joy]

nice kaayo ang power requirement... pwede ra mag SLI using a lower rated PSU...

[siopao1984]

Conclusion



We're pretty sure that most (sanctioned) reviews that you'll read on the Internet today will unashamely proclaim that the GTX 680 is the best single card around, but the truth is most users who buy these cards are going to overclock their cards to the limit and then both Nvidia and AMD flagships are going to trade wins at the top. The lackluster compute performance and inferior memory bandwidth will hurt the GTX 680 in multi-screen, maxed out image quality, high end gaming. We also estimate that the BOM (Bill of Materials) cost on the HD 7970 is higher, given the higher end VRMs/more phases and larger cooling system.

To be fair, we'll have to give it to Nvidia that the GTX 680 is still a very fast card and has significantly better energy efficiencies and clock potential than the Taihiti XT @ 28nm. It is also refreshing that AMD finally has some competition at the top, so we can stop paying ridiculous prices for single GPU boards. We also didn't cover the other features like TXAA and triple display support, but these are gimmicks that are also present in the Radeons. We would like to pit the GTX 680 again with the HD 7970 in multi-GPU scenarios, hopefully 4-way.

With an MSRP at US$499, the GTX 680 sits between the HD 7950 and the HD 7970. If you are just purely using it for gaming purposes, you can buy this card.