NVIDIA GTX 980 Reviewccokeman -
Category: Video Cards
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NVIDIA GTX 980 Introduction:
My does time fly in the video card world as of late. Less than a year ago we saw the coronation of the GTX 780 Ti as the fastest single GPU video card on the market, although AMD took a good shot at the crown with the R9 290X. Just over 10 months from the release of the GTX 780 Ti, NVIDIA brings its replacement to the world in a flurry of new tech and energy efficient performance. All of this centered around the Maxwell GM204-based GTX 980.
Today we get a card that is based on the full implementation of NVIDIA's GM204 Maxwell architecture that NVIDIA promises to be the most advanced card ever. Packed with a feature set that includes all new technologies such as the new third generation lossless Delta Color compression algorithms for the GDDR5 memory to increase bandwidth through a smaller bus, Dynamic Super Resolution that lets gamers downsample 4K resolutions to 1920x1080 to deliver improved visual quality, Multi-Frame Sampled AA that takes some of the performance hit away from using 4xAA at higher resolutions, and all new lighting feature by way of Voxel Global Illumination. All of this is packed into a 10.5-inch package that should retail in the $549 range for the GTX 980. That's anywhere from $50 to $150 less than the current kingpin, the GTX 780 Ti, is selling for today. Let's dig into what makes the GTX 980 tick.
NVIDIA GTX 980 Closer Look:
I had my first look at the Maxwell architecture when I looked at the GM107-based GTX 750 Ti and GTX 750 earlier this year. The architecture was built to maximize energy efficiency and still deliver excellent gaming performance. Now we have the full realization of the architecture labeled as GM204 that takes this to a new level by delivering twice the performance per watt when compared to the early versions of Kepler architecture such as that seen in the GTX 680. NVIDIA has used roughly the same architectural arrangement since Fermi debuted in 2010. From Fermi to Kepler and now Maxwell we see huge improvements.
Looking at the Maxwell architecture, it is based around four graphics processing clusters, each with its own raster engine. Each GPC has a total of four Maxwell Streaming Multiprocessors units, each with a Polymorph engine, 128 CUDA cores, and eight texture units. A quartet of 64-bit memory controllers are used to manage 4GB of 7000MHz rated GDDR5. Each memory controller comes equipped with 16 ROPs and 512KB of L2 cache. Adding that up we get 2048 CUDA cores, a unified shared 2048KB of L2 cache, 64 ROPs, and 128 texture units. Built on NVIDIA's 28nm process, this implementation houses only 5.2 billion transistors compared to 7.1 billion under the lid on the GTX 780 Ti, with a large physical die size of 398 mm². Being built for efficiency and performance you can see how less hardware should relate to the much improved 165 watt power envelope.
Core clock speed comes in at 1126MHz with a Turbo Boost 2.0 clock speed of 1216MHz. Base memory speed on the 4GB of GDDR5 is 1750MHz or an effective rate of 7000MHz running through a 256-bit bus. While this may initially seem to be cause for concern with the status of this card as the fastest, most advanced single GPU on the market, NVIDIA has some additional tech up its sleeves for improving the memory compression techniques to reduce the memory bandwidth needs. By using the new third generation lossless Delta Color compression algorithms, you see a benefit as data is written to and from the GDDR5 memory at up to an 8:1 ratio depending on the size of the pixel block being written. This results in Maxwell needing 25% less bytes of data than a comparable Kepler core. A Kepler core would need a memory data rate of 9.3Gbps to run comparable throughput numbers to Maxwell's architecture.
The GTX 980 arrives in a fashionable two-part foam lined box that not only keeps the hardware safe, but presents it as you slide the upper cover off. This is most likely not what you will see from partners as a package, but may well see in NVIDIA-branded boxes.
At first glance the GTX 980 visually looks like the GTX 780 Ti and uses the same industrial design that we have seen since the introduction of the GTX 690. Externally the only real clues that something is up are the name change, I/O plate, and the use of a functional back plate used to cool the components on the back side of the GTX 980. You get the same magnesium shroud, aluminum frame, and poly carbonate window over the cooling solution seen on the previous cards, so there is that continuity in the looks department.
At 10.5 inches long the GTX 980 is a full sized card that should fit in a wide variety of chassis on the market, from full towers to smaller mATX builds. This card is designed for use in a 16x PCIe 3.0 slot and is backwards compatible. A dynamically managed blower-style fan is used to manage the thermals and noise levels to provide both excellent cooling and a reduced noise profile. The back side of the GTX 980 is covered with a back plate that is equipped with a unique feature: a removable plate just under the dual 6-pin PCIe power connections. NVIDIA found that putting a relief in this area greatly enhanced the flow of air to another card when running an SLI configuration; one of the challenges associated with running up to four cards in SLI.
The I/O connectivity on the GTX 980 gets a new face lift. For the GTX 980, connectivity consists of a single Dual Link DVI port, an HDMI 2.0 port, and a trio of DisplayPort 1.2 ports. The inclusion of the HDMI 2.0 port means that resolutions up to 4K are supported natively with a refresh rate of 60Hz. The maximum resolution supported by the DisplayPort connections is boosted to 5120x3200 at 60Hz. There are a total of five ports and seven links on board that allow the end user to use any four of the connections simultaneously. The use of the trio of DisplayPort connections with G-SYNC ready monitors, such as the ASUS ROG Swift PG278Q, will mean you can get all the performance potential of the GTX 980 without the input lag or screen tearing you get when running with V-Sync enabled or disabled at refresh rates of up to 144Hz. A new grill or I/O plate is used to open up the airflow through the chassis of the GTX 980 and helps to further reduce in-chassis temperatures. The back end of the card has an opening that allows air to be pulled in and help cool parts of the 4+1 phase VRM located on the back end of the GTX 980.
Some of the emphasis on the GTX 980 is how the card is significantly more efficient than even the last generation Kepler cards and significantly more impressive when compared to the first iteration of Kepler on the GTX 680. A pair of 6-pin PCIe power connectors supply 150 watts to the 4+1 phase power system, with an additional 75 watts coming in via the 16x PCIe slot for a total of 225 watts available to feed this 165 watt TDP card. Yes, you read that right, 165 watts is all this card is designed to use under a maximum load. With a TDP this low, the power supply requirements are equally low, with a recommended PSU of 500 watts.
A feature implemented with the GTX 980, and previously used on the GTX 780 Ti, is power balancing circuitry that ensures not one of the three power sources (two 6-pin PCIe and the 16x PCIe slot) will become overloaded by pulling power from a bus that has spare capacity versus one at the capacity limit. A pretty cool feature that can pay benefits when overclocking. A pair of SLI bridge connections show that SLI is still supported and needs a bridge connection to connect the cards in the GTX 980 SLI configuration.
Pulling the magnesium cover off you get to the guts of the card. An aluminum heat sink is used in conjunction with a three heat pipe filled plate to transfer the thermal load from the Maxwell core to the plate, then the aluminum heat sink with the airflow provided by the dynamically controlled blower style fan. Each of the three heat pipes are filled with purified water to aid in heat transfer. An aluminum plate is used to aid cooling the 4+1 phase power circuit and the 4GB of GDDR5 memory. Completely stripped you get to the base level of the GTX 980 to get a view of the card.
Looking at the GTX 980, it appears that we get big clock speeds and some interesting technology improvements to make gaming all that much more enjoyable. The hardware is fun to look at, but let's look at some of the new technologies and then followup with some performance results to see if this replacement for the GTX 780 Ti is a worthy successor.