Image Quality

Generally, recently TXAA provides the best image.  However, Unity’s implementation is not an improvement over Assassin’s Creed IV; it introduces more blur although it does fit in with the game’s “cinematic” look.  TXAA provides very good anti-aliasing approximating 4xMSAA, while the performance hit is less.  The TXAA blur is more than with FXAA, but unlike with FXAA, SMAA and MSAA, the texture crawling and shimmering is nearly gone.  If one desires an even sharper image, SweetFX can usually be used together with TXAA which we did not check out.  4xMSAA is cleaner than 2xMSAA which in turn is an improvement over FXAA.  MFAA will be discussed separately, and it turned out to became our favorite form of AA.

Let’s look at some of the settings individually.

MFAA

MFAA is only available exclusively for Maxwell based GPUs on Nvidia GeForce GTX 980 and GTX 970 graphics cards.  Jagged edges and especially shimmering in motion, are quite noticeable in Unity with no AA enabled.  MSAA reduces the prominence of jagged edges, but does so at a substantial performance cost.

MFAA-1Nvidia’s engineers developed MFAA to reduce this performance cost while delivering comparable image quality to MSAA by varying – in interleaved fashion – the sample patterns used per pixel both spatially in a single frame and interleaved across multiple frames in time. For example, each successive pixel uses one of four different 2x AA sample patterns.  The final result is that MFAA can deliver image quality approaching that of 4x MSAA at roughly the cost of 2x MSAA, or 8x MSAA quality at roughly the cost of 4x MSAA.

By alternating AA sample patterns both temporally and spatially, 4x MFAA has the performance cost of 2x MSAA, with image quality equivalent to 4x MSAA.
By alternating AA sample patterns both temporally and spatially, 4x MFAA has the performance cost of 2x MSAA, with image quality equivalent to 4x MSAA.

Previous-generation GPUs include fixed sample patterns for anti-aliasing (AA) that are stored in Read Only Memory (ROM). If a gamer selects 2x or 4x MSAA, fixed sample patterns are used. With Maxwell, Nvidia has introduced programmable sample positions for rasterization that are stored on Random Access Memory (RAM), creating opportunities for new AA techniques that uniquely address the challenges of modern game engines, such as the increased performance cost of high-quality anti-aliasing. Maxwell’s new RAM-based sample position technology can still be programmed with standard MSAA and TXAA patterns, but now the driver or application may also load the RAM with custom positions that are free to vary from frame to frame, or even within a frame.

The first implementation of MFAA is compatible with GeForce GTX 980, GTX 970, GTX 980M, and GTX 970M GPUs, and supports the following technologies and platforms:

Multisampling anti-aliasing (2x or greater)
Adaptive VSync
Dynamic Super Resolution (DSR)
G-SYNC
Optimus
DirectX 10/11
Standard VSync
Ultra-high resolutions
Virtual Reality

MFAA has been enabled with a new WHQL driver publicly released today, 344.75 which we have been able to preview.  The first games that are supported are:

Assassin’s Creed IV: Black Flag
Assassin’s Creed: Unity
Battlefield 4
Civilization: Beyond Earth
Civilization V
Crysis 3
DiRT 3
DiRT Showdown
Far Cry 3
Far Cry: Blood Dragon
F1 2013
F1 2014
GRID 2
GRID Autosport
Hitman: Absolution
Just Cause 2
Saints Row IV
Splinter Cell: Blacklist
Titanfall
Wargame: European Escalation

MFAA w980To enable it, just go to Nvidia’s control panel.

MFAA is a new AA mode which is supposed to give the same quality as 4x MSAA but with only the performance costs of 2x MSAA, or the same image quality as 8xMSAA with the performance costs of 4xMSAA. MFAA is based on a Temporal Synthesis Filter with coverage samples per frame and per pixel.

The filter’s performance hit is low.  According to Nvidia, the typical performance advantage over MSAA is 10 to 30%.

Nvidia recommends that MFAA not be combined with other forms of post processing AA such as FXAA or TXAA.  And MFAA requires at least 2xMSAA to function.  We will examine this in our performance and IQ section following this one.

TXAA

TXAA is a cinematic-style anti-aliasing technique designed specifically to reduce temporal aliasing (crawling and flickering in motion). TXAA is a mix of hardware AA, custom CG film style AA resolve, and a temporal filter. To filter any given pixel on the screen, TXAA uses a contribution of samples both inside and outside of the pixel in conjunction with samples from prior frames. The trade-off is blur, which for some is intolerable and for others, cinematic. This editor much prefers the mild blur of TXAA to the texture crawling and flickering while in motion without.

TXAA has improved spatial filtering over standard 2x MSAA and 4x MSAA, particularly on fences or foliage. TXAA is also capable of intelligently managing per-pixel effects without introducing lighting artifacts on object edges. The filtering used by TXAA results in a softer image compared to traditional MSAA – the blur.

TXAA uses hardware MSAA in conjunction with a temporal filter. The performance hit of TXAA will vary from game to game and is directly correlated to the performance hit of MSAA. In this game, TXAA takes less of a performance hit than 4xMSAA. Screen shots look better with MSAA, but playing the game with the camera in motion or even a video capture can easily show the advantages of TXAA.

NVIDIA HBAO+

To advance Screen-Space Ambient Occlusion (SSAO) tech, Nvidia’s HBAO+ looks better than the original HBAO algorithm, especially on scenes with thin objects such as grass and leaves. It is now fast enough to be used by top GPUs.

Percentage-Closer Soft Shadows (PCCS) 

Percentage-Closer Soft Shadows (PCSS) is a technique designed to simulate the natural softening of shadows that occurs over increasing distance from the occluding object. PCSS provides three notable improvements over hard shadow projections: shadow edges become progressively softer the further they are from the shadow caster, high-quality filtering reduces the prominence of aliasing, and the use of a shadow buffer allows PCSS to handle overlapping character shadows without creating “double-darkened” portions.

In addition, Assassin’s Creed Unity offers 4K textures – something probably best experienced by Tri- or Quad-SLI’d GTX 980s, although unfortunately MFAA does not yet work with multi-GPU, something Unity would benefit from greatly.

DRM

Assassin’s Creed Unity uses UbiSoft’s proprietary Uplay to launch the game and the gamer must connect to the Internet at least once.  Once the game is authenticated, the game can be played in offline mode on the PC it was installed on, and it never requires the game to be updated.  However, it is to the single player’s advantage to play while connected to the Internet as there are more options available.  Unfortunately, since the last patch we experience a bug where the game will not launch at all in the offline mode.

ACU 2014-11-14 19-59-30-54The performance/IQ analysis and MFAA

Check the next page for the performance and IQ evaluation of Assassin’s Creed Unity.  First, let’s check out the complete test bed.

Test Configuration – Hardware

  • Intel Core i7-4770K (reference 3.5GHz, HyperThreading and Turbo boost is on to 3.7GHz; overclocked to 4.0GHz; DX11 CPU graphics), supplied by Intel.
  • ECS GANK Domination Z87H3-A2X motherboard (Intel Z87 chipset, latest BIOS, PCIe 3.0 specification, CrossFire/SLI 8x+8x) supplied by ECS
  • 16 GB DDR3 HyperX Kingston “Beast” RAM (2×8 GB, dual-channel at 2133MHz; supplied by Kingston)
  • Kingston 240GB mSATA SSD used for caching the HDD, supplied by Kingston
  • GeForce GTX 780 Ti 3GB (reference clocks), supplied by Nvidia
  • GeForce GTX 780 3GB (reference clocks), supplied by Nvidia
  • GeForce GTX TITAN, 6GB (reference clocks), supplied by Nvidia
  • GeForce GTX 980, 4GB reference clocks, supplied by Nvidia
  • Nvidia GTX 770, 2 GB reference design and clocks, supplied by Nvidia
  • Onboard Realtek Audio
  • Genius SP-D150 speakers, supplied by Genius.
  • Two 2TB GB Toshiba 7200.10 hard drive identically configured; 1 for Nvidia and 1 for AMD
  • Cooler Master 1000W power supply unit supplied by Cooler Master
  • Thermaltake Water2.0 Pro watercooler, supplied by Thermaltake
  • Thermaltake Overseer RX-I full tower case, supplied by Thermaltake
  • ASUS BW-12B1ST 12X Blu-Ray writer
  • HP LP3065 2560×1600 thirty inch LCD.
  • ASUS 1920×1080, 27″ LCD, 120Hz
  • HyperX Cloud gaming headset, supplied by Kingston

Test Configuration – Software

  • Nvidia GeForce WHQL 344.75. High Quality; Single-display Performance mode; Prefer Maximum Performance. Shader Cache on, Vsync off.
  • Windows 7 64-bit; very latest updates
  • EVGA PrecisionX overclocking and monitoring software; temperature and power targets set to maximum.
  • Latest DirectX
  • Varying AA enabled including MFAA for the GTX 980
  • All results show average frame rates
  • Highest quality sound (stereo) used in all games.
  • Windows 7 64-bit, DX11
  • Latest version of Fraps

 

  • Windows 7 64, all DX9 titles were run under DX9 render paths, DX10 titles were run under DX10 render paths and DX11 titles under DX11 render paths.

The Game

  • Assassin’s Creed: Unity, digital reviewer’s copy; Supplied by Ubisoft/Nvidia

Let’s check the performance, settings and the Image Quality (IQ) on the next page.