Overclocking NVIDIA's GTX 980 Ti Graphics Card - A 19% Performance Gain

By Published June 01, 2015 at 8:35 am
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Our initial review of the $650 GTX 980 Ti, published just over twelve hours prior to this post, mentioned an additional posting focusing on the card's overclocking headroom. The GTX 980 Ti runs GM200, the same GPU found in nVidia's Titan X video card, and is driven by Maxwell's new overclocking ruleset.

Maxwell, as we've written in a how-to guide before, overclocks differently from other architectures. NVidia's newest design institutes a power percent target (“Power % Target”) that increments power provisioning to the die to grant OC headroom. Unfortunately, this metric can't be exceeded beyond what the BIOS natively allows (without a hack, anyway), and means that we're sharing watts between the core clock, memory clock, and voltage increase. Overclocking on Maxwell offers some granularity without making things too complicated, though it's not until we get hands-on with board partner video cards that we'll know the true OC ceiling of the 980 Ti.

This post showcases our GTX 980 Ti initial overclock on the reference cooler, yielding a considerable framerate gain in game benchmarks.

NVidia GTX 980 Ti Specs

  GTX 980 Ti GTX Titan X GTX 980
GTX 780 Ti 
GPU GM200 GM200 GM204 GK-110
Fab Process 28nm 28nm 28nm 28nm
Texture Filter Rate
(Bilinear)
176GT/s 192GT/s  144.1GT/s 210GT/s
TjMax 92C 91C  95C 95C
Transistor Count 8B 8B  5.2B 7.1B
ROPs 96  96 64 48
TMUs 176  192 128 240
CUDA Cores 2816 3072  2048 2880 
Base Clock (GPU) 1000MHz 1000MHz  1126MHz 875MHz 
Boost Clock (GPU) 1075MHz 1075MHz  1216MHz 928MHz 
GDDR5 Memory /
Memory Interface
6GB / 384-bit 12GB / 384-bit 4GB / 256-bit  3GB / 384-bit
Memory Bandwidth (GPU) 336.5GB/s 336.5GB/s  224GB/s 336GB/s
Mem Speed  7Gbps 7Gbps 7Gbps
(9Gbps effective - read below) 
7Gbps 
Power  1x8-pin
1x6-pin
1x8-pin
1x6-pin 
2x6-pin  1x6-pin
1x8-pin 
TDP  250W 250W 165W  250W 
Output 3xDisplayPort
1xHDMI 2.0
DVI
3xDisplayPort
1xHDMI 2.0
1xDual-Link DVI
DL-DVI
HDMI 2.0
3xDisplayPort 1.2
1xDVI-D
1xDVI-I
1xDisplayPort
1xHDMI
MSRP $650 $1000 $550 now $500 $600

Test Methodology

We tested using our updated 2015 GPU test bench, detailed in the table below. Our thanks to supporting hardware vendors for supplying some of the test components. Thanks to Jon Peddie Research for GTX 970 & R9 280X support.

The latest GeForce press drivers were used during testing. AMD Catalyst 15.5 was used. Game settings were manually controlled for the DUT. Stock overclocks were left untouched for stock tests.

VRAM utilization was measured using in-game tools and then validated with MSI's Afterburner, a custom version of the Riva Tuner software. Parity checking was performed with GPU-Z. FPS measurements were taken using FRAPS and then analyzed in a spreadsheet.

Each game was tested for 30 seconds in an identical scenario on the two cards, then repeated for parity.

GN Test Bench 2015 Name Courtesy Of Cost
Video Card

GTX 980 Ti 6GB

NVIDIA $650
CPU Intel i7-4790K CPU CyberPower
$340
Memory 32GB 2133MHz HyperX Savage RAM Kingston Tech. $300
Motherboard Gigabyte Z97X Gaming G1 GamersNexus $285
Power Supply NZXT 1200W HALE90 V2 NZXT $300
SSD HyperX Predator PCI-e SSD Kingston Tech. TBD
Case Top Deck Tech Station GamersNexus $250
CPU Cooler Be Quiet! Dark Rock 3 Be Quiet! ~$60

Average FPS, 1% low, and 0.1% low times are measured. We do not measure maximum or minimum FPS results as we consider these numbers to be pure outliers. Instead, we take an average of the lowest 1% of results (1% low) to show real-world, noticeable dips; we then take an average of the lowest 0.1% of results for severe spikes.

We conducted a large suite of real-world tests, logging VRAM consumption in most of them for comparative analysis. The games and software tested include:

We already know ACU and Far Cry 4 consume massive amounts of video memory, often in excess of the 2GB limits of some cards. GRID: Autosport and Metro: Last Light provide highly-optimized benchmarking titles to ensure stability on the bench. Shadow of Mordor, GTA V, & Battlefield Hardline (not shown here) are new enough that they heavily eat RAM. 3DMark offers a synthetic benchmark that is predictable in its results, something of great importance in benchmarking.

Games with greater asset sizes will spike during peak load times, resulting in the most noticeable dips in performance on the 2GB card as memory caches out. Our hypothesis going into testing was that although the two video cards may not show massive performance differences in average FPS, they would potentially show disparity in the 1% low and 0.1% low (effective minimum) framerates. These are the numbers that most directly reflect jarring user experiences during “lag spikes,” and are important to pay attention to when assessing overall fluidity of gameplay.

Overclocked tests were conducted using MSI Afterburner for application of settings. All devices were tested for performance, stability, and thermals prior to overclocking to ensure clean results. On the OC bench, devices were set to maximize their voltage ceiling with incremental gains applied to the core clock (GPU) frequency. MSI Kombustor, which loads the GPU 100%, was running in the background. Once stability was compromised -- either from crashing or artifacting -- we attempted to resolve the issue by fine-tuning other OC settings; if stability could not be achieved, we backed-down the core clock frequency until we were confident of stability. At this point, the device was placed on a burn-in test using Kombustor and 100% load for 30 minutes. If the settings survived this test without logged fault, we recorded the OC settings and logged them to our spreadsheet.

Final OCs were applied and tested on games for comparison.

Thermals were reported using Delta T over ambient throughout a 30-minute burn-in period using 3DMark FireStrike - Extreme, which renders graphics at 1440p resolution. This test loads the VRAM heavily, something Kombustor skips, and keeps the GPU under high load that is comparable to gaming demands. Temperatures were logged using MSI Afterburner.

Overclocking Results

CLK Offset Max Clock Mem Offset Mem CLK Voltage Initial Test Endurance?
+68MHz 1245MHz +500MHz 4001MHz  1.187V Pass N/A 
+100MHz 1289MHz  +500MHz 4001MHz 1.187V Pass  N/A 
+150MHz 1339MHz  +500MHz  4001MHz  1.187V  Pass  N/A 
+175MHz 1364MHz  +500MHz  4001MHz  1.187V  Pass  N/A 
+200MHz 1389MHz  +500MHz  4001MHz  1.187V  Pass  N/A 
+225MHz 1414MHz  +500MHz  4001MHz  1.187V  Pass N/A 
+250MHz 1439MHz  +500MHz  4001MHz  1.187V  Pass  N/A 
+275MHz 1464MHz +500MHz 4001MHz 1.187V Fail Fail
+250MHz 1427MHz +500MHz 4001MHz 1.187V Pass Pass
+255MHz 1444MHz +500MHz 4001MHz 1.187V Pass Pass
+260MHz 1450MHz +500MHz 4001MHz 1.187V Pass Fail

For overclocking, we configure the power percent target to its maximum value before adjusting voltage to its own max setting. The 980 Ti allows 110% of base power to be supplied to the GPU for overclocking and seems to hover around 1.187V after overvolting. We then slowly increment clockrate, observing for visual artifacting or catastrophic failures throughout the process. Each increment is left only for a few minutes before moving to the next step. We're eventually confronted with a driver failure, at which point the clockrate is backed-down and then endurance tested for 20-minutes using Kombustor.

Kombustor, an MSI-branded Furmark, is used for burn-in testing and stability. Running Kombustor forces the GPU to see 100% utilization, which evokes the highest boost clock possible under the current clock settings. We left the memory clock to +500MHz, though it could assuredly be pushed further.

The results are above.

We were able to achieve a stable frequency at +255MHz over base (1000MHz), achieving an output of 1444MHz max boost clock. Voltage throughput was logged at 1.187V.

Let's look at the performance difference after overclocking.

GTX 980 Ti Overclocking Benchmark

oc-980ti-mll-4k

oc-980ti-mordor-4k

oc-980ti-witcher-4k

oc-980ti-witcher-1440

oc-980ti-grid

The GTX 980 Ti pushed an impressive clockrate over base, resulting in great gains in some games. The Witcher 3 at 4K sees a jump from 33FPS average to 40FPS average, with a massive 2x gain in 1% low FPS. At this point, the game becomes truly playable at 4K after lowering foliage viewing distance, bringing the framerate closer to 50FPS.

1440p sees a similar jaunt for the GTX 980 Ti. The card moves to 68FPS, ranked against the Titan X at 59FPS and 980 Ti base at 57FPS.

Shadow of Mordor also produces a ~10FPS gain over base and noteworthy gain over the TiX base at 4K.

GRID: Autosport is a bit of an anomaly with the 980 Ti, and I'm not entirely sure why. This is the one game where we see a large disparity in framerate between the Titan X and 980 Ti, and that continues here; gains are still noteworthy after overclocking, though.

The overall performance gain sits at about +19% for the GTX 980 Ti, a marked improvement with minimal effort. Note that the reference cooler is throttling us at this +255 configuration and could become a concern for longevity of the GPU. We haven't received any yet, but aftermarket GPU coolers designed by board partners should greatly improve overclocking potential. EVGA's liquid-cooled 980 Ti looks particularly promising.

Read the full GTX 980 Ti review here.

Last modified on June 01, 2015 at 8:35 am
Steve Burke

Steve started GamersNexus back when it was just a cool name, and now it's grown into an expansive website with an overwhelming amount of features. He recalls his first difficult decision with GN's direction: "I didn't know whether or not I wanted 'Gamers' to have a possessive apostrophe -- I mean, grammatically it should, but I didn't like it in the name. It was ugly. I also had people who were typing apostrophes into the address bar - sigh. It made sense to just leave it as 'Gamers.'"

First world problems, Steve. First world problems.

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