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 353.06 drivers were used during testing. AMD Catalyst 15.5 was used. Game settings were manually controlled for the DUT. Clock-for-clock tests were performed, overclocking reference to ~1140MHz against the Hybrid. Note that, due to the way boost clocks work, a perfectly identical clockrate is not always possible -- but we can get close.
VRAM utilization was measured using in-game tools and then validated with MSI's Afterburner and AIDA64, 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|
|CPU||Intel i7-4790K CPU||CyberPower
|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:
- Far Cry 4 (Ultra 1080, Very High 1080).
- GRID: Autosport (Ultra 1440, Ultra 4K).
- Metro: Last Light (Very High + Very High tessellation at 1080; High / High at 1440).
- GTA V (Very High / Ultra at 1080p).
- Shadow of Mordor (Very High, 1080p).
- 3DMark Firestrike Benchmark
- GTA V
- The Witcher 3
We already know GTA V 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, & The Witcher 3 are new enough that they heavily eat VRAM. 3DMark offers a synthetic benchmark that is predictable in its results, something of great importance in benchmarking.
Overclocked tests were conducted using EVGA Precision 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. 3DMark Firestrike was used on infinite loop to determine stability in a relatively real-world scenario. 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 3DMark Firestrike for 25 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 25-minute burn-in period using 3DMark FireStrike - Extreme on infinite loop, 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 AIDA64.
|CLK Offset||Max Clock||Mem Offset||Mem CLK||Voltage||Initial Test||Endurance?|
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 1.224V 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 25-minutes using 3DMark Firestrike Extreme on loop.
We were able to get the 980 Ti Hybrid to perform with stability at +160MHz offset, or 1514MHz. There was a brief period of stability at +170MHz (1524MHz boost), but volatility was found approximately twenty minutes into burn-in testing. We left the memory clock OC'd to +500MHz offset, though it could likely be pushed further with granular tweaking. Our main concern is the core and boost clocks.
To this end, a 1514MHz final clock is a significant improvement over the GTX 980 Ti reference model's ~1444MHz resting place. Here's the table for our GTX 980 Ti (reference) overclocking steps:
|CLK Offset||Max Clock||Mem Offset||Mem CLK||Voltage||Initial Test||Endurance?|
Note that the offsets are higher for the reference model because it has a lower starting place. We performed clock-for-clock thermal testing between the two cards, found in the next section.
GTX 980 Ti Hybrid Thermals vs. Reference
We've got two charts above and one below, in this order: Line graph of thermals over time, bar graph of average temperatures once equilibrium is reached, and below, a bar graph of measured power consumption in wattage of the GTX 980 Ti and GTX 980 Ti Hybrid. The test period for the temporal chart was 25 minutes.
EVGA's GTX 980 Ti Hybrid keeps itself cooler for longer once the GPU falls under heavy load and, as made obvious above, has a substantially lowered maximum temperature. Thermals of the EVGA 980 Ti Hybrid are hands-down impressive at a temperature reduction of more than 2X. The Hybrid's 100% loaded thermal range is 22.91C to 24.04C (overclocked), with the clock-for-clock 980 Ti reference at 61.92C and stock at 61.39C. That's a massive difference. After adding ambient back in, our GPUs were sitting in the 40s with the Hybrid and in the 80s with the reference cooler design, which is approaching TjMax of the diode.
The thermal reduction alone is “worth” the added price, but can be hard to swallow for some buyers. Reducing thermals of the GPU will reduce temperatures of the neighboring CPU, RAM, and chipset, driving down temperatures of the system in its entirety. Lower temperatures mean lower fan operating speeds – the CPU can throttle-down, as can the case fans – and thus lower acoustics.
After looking at FPS performance in games, we'll have a better understanding of ROI on the Hybrid. First, watts consumed:
Power is effectively identical between the two cards, so Asetek's solution doesn't draw a noteworthy gain over reference.
GTX 980 Ti Hybrid Benchmark – Far Cry 4
Far Cry 4 sees slightly boosted performance over the Titan X, something the reference GTX 980 Ti was uncapable of achieving given the marginally lower core count. This is noteworthy and assists in the price increment of EVGA's card. Although it's not shown in these charts, overclocking the reference GTX 980 Ti would also outperform the Titan X -- something we tested here.
GTX 980 Ti Hybrid Benchmark – GTA V
Clockrate increases are reflected most heavily in GTA V when the "Advanced Settings" are maximized, with the difference producing effectively insignificant results with these settings disabled or lowered. The Hybrid offers a great performance boost in this instance and remains tied with the reference 980 Ti in the 4K, non-advanced-settings test.
GTX 980 Ti Hybrid Overclock Benchmark – The Witcher 3
GTX 980 Ti Hybrid Overclocking Benchmark – Metro: Last Light
GTX 980 Ti Hybrid Overclocking Benchmark – Shadow of Mordor
Performance gains are a bit more volatile and unpredictable with the GTX 980 Ti Hybrid when compared against the Titan X and SLI 980 Tis. The SLI testing reflects inconsistencies in software optimization for multi-GPU configurations and also utilizes two GPUs, so isn't exactly the same market as a single Hybrid would be.
Looking at the 980 Ti Hybrid and the Titan X, we see the two trade blows in a few places, but are generally sitting near one another. Some games, like GTA V at 1080p with maximized advanced settings, reflect a massive performance gain strictly from the boosted core clock. When GTA V uses no advanced settings (but 4K with maximum core graphics options), we see a much smaller ~1FPS margin of error gain over the Titan X. Because the architecture is identical and the only real differences come in the clockrate and RAM – which won't get saturated at 6GB, anyway – the biggest performance gains are reflected by the clock increase.
Far Cry 4 shows tied 1080p performance at the top-end due to a likely CPU bottleneck, but 4k performance shows a 2FPS gain in the 980 Ti Hybrid over the TiX and a ~5FPS gain over the reference design. When we look to overclocking, the 980 Ti Hybrid has large gains over its stock clock at 68FPS (1440p) against 61FPS (1440p stock), but is matched nearly equally with the 980 Ti at all levels of the clock. Overclocking the Hybrid card doesn't immediately produce unbeatable framerates by the reference design or stock Titan X, but there's more to the story than that: With a substantially lower thermal footprint, the Hybrid version of the card – although it performs similarly to the 980 Ti reference at overclocked levels – is >2X cooler and will offer a longer lifespan resultant of the reduction in thermals. The card will also hold equivalent overclocks with less effort, so modest OCs can be applied with marginally lower voltage.
The 980 Ti Hybrid does have an added cost, but it generally performs better than or equal to the Titan X at its stock clocks. The value-add from liquid cooling is significant and should be acknowledged by anyone seeking to overclock the card or reduce overall system thermals. An SFF box, for instance, would see great gains from the liquid cooled card if there's room for the radiator. At an added ~$120, the card may enter inaccessible pricing territory for some high-end users. If this is the case, the reference 980 Ti is still a solid performer and is cooled well enough, but shouldn't be overclocked as aggressively as the 980 Ti Hybrid.
Our Editor's Choice and Best of Bench awards go to EVGA for its high-performance, exceptionally cool execution of a liquid-cooled GTX 980 Ti.
- Steve “Lelldorianx” Burke.