Enter Maxwell

Nvidia rolled out its first add-in board based on its most efficient design to date, its Maxwell architecture. The GTX 750 TI, an entry-level product, is the first AIB with the Maxwell architecture to hit the street. It might seem a bit unusual to roll out the Maxwell architecture with an entry-level card; in the past, product lines come out first with    the flagship and follow up with performance segment SKUs and then the mainstream/entry-level products. But, given that one of the most impressive aspects of Maxwell is power efficiency and performance per watt, introducing the line with an entry-level card makes perfect sense in this case.   

The primary contributor to Maxwell’s improved efficiency is its streaming multiprocessor (SM) architecture. The new SM architecture, which Nvidia now calls SMM—Streaming Multiprocessor Maxwell—achieves much higher power efficiency, and Nvidia claims it gets 35% more performance per CUDA core on shader-limited workloads. The organization of the SM has also been changed. Each SM now has four processing blocks, each with its own instruction buffer, scheduler, and 32 CUDA cores. The Kepler approach of having a non-power-of-two number of CUDA cores, with some of them shared, is eliminated. This partitioning simplifies the design and scheduling logic, saving area and power, and reduces computation latency. Overall, with this new design, each SM is significantly smaller while, says Nvidia, delivering about 90% of the performance of a Kepler SM, and the smaller area enables Nvidia to implement many more SMs per GPU. This process, claims the company, has allowed Nvidia to achieve 2X more power efficiency in a year’s  time, without the need to go beyond 28 nanometers.   

Physically the AIB is 5.7 inches in length and 4.4 inches in width, the same dimensions as the previous generation AIB, the GTX 650 TI. This small size imakes the 750 TI versatile, allowing it to be used in various form factors.  When put in a tight Xigmatek Nebula mini-ITX (in a slick Asrock case with an AMD 3.1-GHz A8 7600 APU), it fit without a problem.

The stock heat sink and fan is smaller than the 650 TI, which makes sense given that it runs cooler. The GTX 750 TI also has the advantage of not requiring a 6-pin connector because of its low power demands; this is a major upgrade over previous generations, especially considering the smaller power supplies in the mini form factors as well as the lack of cooling.

One also will notice the lack of the SLI connector tab. The entry-level Maxwells do not support SLI. Nvidia says that there are not enough SLI users in this segment to justify its inclusion. The GTX 750 TI has two DVI ports as well and a mini-HDMI port.

We really love testing the entry-level cards; the engineers’ talents are put to the test with the need to pull out all the stops when it comes to power efficiency and AIB real estate, all the while giving the consumer enough performance to justify the $149 upgrade. Nvidia E-men usually rise to the challenge, supplying excellent performance in the constraints inherent to the entry level, and the GM107 GPU used on the GTX 750 TI AIB is no exception.

Comparison between Nvidia’s Kepler and Maxwell shader organization.

 

 

We ran the AIBs through a variety of tests but will focus on performance in Tomb Raider, Hitman: Absolution, Bio-Shock Infinite, and a couple of synthetic benchmarks.

Given that the GTX 750 TI is a entry-level board, we ran our tests at 1920 x 1080 with “high” presets when available; anti-aliasing and other features were turned off.

The in-game results of the four tests are shown in the charts on the following page.

Pmark

The Nvidia GTX 750TI gets a 53% better Pmark score than the previous GTC 650 TI.

As might be expected, the GTX 750 TI AIB outperforms Intel’s integrated HD 4600 GPU by 3.5X to 4X in many cases, and the AMD A8 Kaveri APU by 2X—this is critical when it comes to justifying the $149 upgrade to entry-level gamers. It  just goes to prove that internal graphics are still nowhere close to competing with even entrylevel add-in boards.

What do we think?

The GTX 750 TI is an outstanding edition to the entrylevel sweet spot in the market. The Maxwell power efficiency and performance/watt are really impressive—    you usually do not see that kind of power efficiency upgrade without an upgrade in the GPU’s nanometer process. The board runs beautifully in HD resolutions, when the GTX 650 TI 1280 x 720 resolution was still acceptable at at entry level—Maxwell has also raised that bar. This board is an impressive piece of technology and provides excellent value.—R.D.