Nvidia GeForce GTX 980 Ti 6GB Review - Tom'sHardwareFewer than three months have passed since Nvidia took the wraps off of GeForce GTXTitan X, and the company is already launching another GM200-based graphics cardcalled GeForce GTX 980 Ti. Its about $400 cheaper than the flagships street price.Yet, were told it only gives up a few percentage points of performance. Is there still areason to lust after the Titan X? Could you, in good conscience, spend $500 on the980 knowing that this monster exists (yes, the 980 is dropping $50, according toNvidia)? Is this move preempting AMDs upcoming ultra-high-end Fiji unveiling?

Any answer to that last question would be purely speculative. But we werentexpecting to see a Titan X derivative so soon. Nvidia introduced its original GeForceGTX Titan in February of 2013 and followed up nine months later with GeForce GTX780 Ti, also based on the GK110 GPU. Those cards were decidedly not built for thesame customers. The Titan had one of its SMX clusters turned off, a then-unprecedented 6GB of memory and a GPU equally adept at 3D and double-precisionmath. Meanwhile, the 780 Ti featured a full 2880 CUDA cores and 240 texture unitsfor graphics supremacy, higher clock rates and a $300-lower price tag. Most gamerswith money to spend had little trouble choosing 780 Ti over the Titan.

Unfortunately, there was also a good reason to ding it: Nvidia armed GeForce GTX780 Ti with 3GB of memory, and the rumored 6GB models never materialized. Twoyears ago, that was fine for 2560x1440. And 4K screens werent really a thing yet;those that did exist were $3000+ affairs. We did, however, figure out that 3GB wasntenough RAM to game smoothly on a trio of QHD displays (>11 million pixels). Later,we also ran into situations where 4K (>8 million pixels) was held back by the cardsavailable memory.

Todays monitor market looks nothing like it did then. Ultra HD screens start under$500. Nvidias G-Sync variable refresh rate technology is almost 18 months-old. AndAMDs FreeSync equivalent is gaining momentum as well. We have to assume thatanyone shopping for a high-end graphics card in 2015 is at least considering anupgrade to 4K.

Tweaking GM200 For GeForce GTX 980 Ti

Nvidia knows where the display market is heading, and it isnt about to shortchangethis generations Titan-derivative in the memory department. Beyond adding moreon-board GDDR5 than 780 Ti, the companys Maxwell architecture utilizes availablebandwidth to greater effectsomething we first observed last February from GeForceGTX 750 Ti and its GM107 GPU. GM200 is built even more robustly than that earlyimplementation of Maxwell. Each of its SMMs sports 96KB of shared memory and a48KB texture/L1 cache, while a large 3MB L2 cache minimizes requests made toDRAM as much as possible. All of those hardware-oriented changes, combined withnew color compression schemes, make playable performance at 4K a more realisticgoal for certain single-GPU systems.

Thats the good news. But because Nvidias GeForce GTX Titan X already features afully-enabled GM200 processor, theres really no way to make the 980 Ti faster. Thiscreates a bit of an issue for differentiating two high-end cards based on the sameASIC.

How about characterizing their strengths in compute-oriented workloads? Lastgeneration, the Titan was capable of around 1.5 TFLOPS of double-precision math.Nvidia artificially dialed the 780 Ti to 1/8 of that, or roughly 210 GFLOPS, creating anice split between them. But the same option isnt available today, since GM200 givesup its compute potential altogether in favor of efficient gaming. As a result, the TitanX and 980 Ti are both limited to native FP64 rates of 1/32.

So, with Titan X already out there, selling for more than $1000, the companys onlyoption seemed to be a surgical incision, trimming away some of GM200s resourcesand creating a GeForce GTX 980 Ti thats slightly less potent than Titan X, but morecompelling than GeForce GTX 980 (and a big upgrade over 780 Ti).

At least the haircut isnt dramatic. Were still looking at GM200 and its six GraphicsProcessing Clusters. Only, across that sextet, two Streaming Multiprocessors aredisabled. With 128 CUDA cores per SMM, youre down 256, yielding a total of2816 cores across the processor. Similarly, the loss of eight texture units perSMM results in a GPU with 176 (instead of 192).

You might guess that fusing off ~8% of GM200s shader and texturing resourceswould result in a corresponding performance drop in games bound by those parts ofthe graphics pipeline. But Nvidia claims that the difference between GeForce GTXTitan X and 980 Ti is minor.

The company doesnt seem to be worried. It isnt trying to compensate with higherclock ratesGeForce GTX 980 Ti is marketed at the same 1000MHz baseand 1075MHz GPU Boost clock rates as Titan X. And the GPUs back-enddoesnt change either. From our Titan X story:

GeForce GTX 980s four ROP partitions grow to six in (GeForce GTX 980 Ti). With16 units each, thats up to 96 32-bit integer pixels per clock. The ROPpartitions are aligned with 512KB slices of L2 cache, totaling 3MB in GM200. Whenit introduced GeForce GTX 750 Ti, Nvidia talked about a big L2 as a mechanism forpreventing bottlenecks on a relatively narrow 128-bit memory interface. Thats notas big of a concern with GM200, given its 384-bit path populated by 7 Gb/smemory. Maximum throughput of 336.5 GB/s matches the GeForce GTX 780 Ti,and exceeds GeForce GTX Titan, GeForce GTX 980 and Radeon R9 290X.

Whereas the Titan X sports 12GB of GDDR5 memory, though, the GeForce GTX 980Ti comes with 6GB at the same 7 Gb/s. Thats hardly a compromise, wed say. Sixgigabytes is plenty for 4K or three QHD screens in Surround. Dont expect to see

12GB versions down the road, either. Nvidia doesnt plan to chew into Titan X saleswith a beefed-up 980 Ti.

This cards story continues much like the Titan X before it, then. Nvidias GM200drops onto the same 10.5-long PCB, making life easy for anyone who might bereplacing a GeForce GTX 780 Ti.

Because the 980 Ti halves Titan Xs memorysubsystem, there are no packages on the backof the board; theyre all on the front. Twelveemplacements host 4Gb (512MB) ICs, whichadd up to 6GB. Youll also notice the two SLIconnectors at the top of the board. As

expected, the GeForce GTX 980 Ti supports up to four-way configurations.

Nvidia again eschews the rear plate featuredon its GeForce GTX 980. Apparently, the TitanX and 980 Ti are more likely candidates forSLI, and the improved airflow between dual-slot cards outweighs any reason to fill thatspace with extra metal.

Again, from our GeForce GTX Titan X review,A plate sits on top of the PCB, cooling anumber of the surface-mounted components.Theres a copper vapor chamber mounted tothat, topped by a two-slot-tall aluminum heatsink. Nvidias reference design remains

faithful to the centrifugal fan, which pulls in air from your chassis, pushes it over theplate, through the heat sink and out the back. Although blower-style fans tend tocreate more noise than axial coolers, weve seen enough cards based on this same IDto know theyre acoustically-friendly. (GeForce GTX 980 Ti) is no exception.

In an effort to maintain the Titan Xs premium aesthetic, GeForce GTX 980 Ti iscovered in an arguably less aggressive silver-colored aluminum shroud than theflagship. Its the exact same color and texture as Nvidias 780 Ti. One small difference

exists: theres an extra bit of metal by the I/Obracket covering the bottom-most DisplayPortand DVI connector frames. This area waspreviously exposed.

Like the GeForce GTX Titan X and 980, 980 Tiincludes one dual-link DVI port, one HDMI2.0-capable connector and three full-sizedDisplayPort interfaces. Between those fiveoptions, you can drive as many as four displaysat a time. And if youre using G-Sync-enabled

displays, that trio of DisplayPort 1.2 outputs makes Surround a viable choice. Incomparison, 780 Ti came with two DVI outputs, one HDMI 1.4a port and a full-sizeDisplayPort connector. Changes to the way enthusiasts are attaching their monitorsare clearly affecting what Nvidia does with its display controller, reflected in a slowshift away from DVI, the addition of HDMI 2.0 support and more DP connectivity.

Power is delivered to the card through its PCIe slot (up to 75W), one six-pin auxiliaryconnector (another 75W) and one eight-pin lead (up to 150W). All told, though, 980Ti is rated at the same 250W TDP as Titan X, and our benchmarks will indeed showthat the two cards demonstrate similar consumption.