HiGame

Over the last couple of days we’ve discussed Assassin’s Creed Unity’s poor reviews, bugginess, and the Xbox One’s surprising lead over the PS4. Now, it’s time to take a closer look at the PC version, and to see just how bad the performance situation is — and to try and work out why that’s the case.

One reason we’ve already heard is that the draw call count on the PC side is very high under certain circumstances — higher, in fact, then DX11 can reasonably support. We’ve rounded up a GTX 780, a GTX 980, and the Radeon R9 290X and put them through their respective paces to see how the game performs — and what users can do to boost frame rates. We’ll also be looking at what effect (if any) Unity’s use of GameWorks has on Nvidia and AMD GPUs.

GameWorks integration and graphics quality

Assassin’s Creed Unity uses GameWorks for ambient occlusion (HBAO+) and for Percentage Closer Softer Shadows (PCSS). It also supports the use of Cascaded Shadow Maps. All three of these technologies are designed to improve rendering by casting realistic and varied types of shadows — PCSS computes shadow penumbras based on the camera’s distance from the occluded object, for example.



High shadows on the left, PCSS shadows on the right

Nvidia’s GeForce.com website offers interactive sliders that you can position over an area of the image to examine the impact of specific features. PCSS is shown above; ambient occlusion below:



Graphically, Assassin’s Creed Unity is gorgeous, but there are two visual issues readers will want to be aware of. First, there’s the pop-in. Games often make subtle use of pop-in to quickly load area data, but Unity will pop people into a scene directly in front of you. Streets that looked empty suddenly have 5-7 people walking in them as you approach. Texture details also tend to pop noticeably as you approach objects.

The other poor aspect of Assassin’s Creed Unity’s graphics is that they’re a mass of crawling, jagged lines. The game makes heavy use of two materials that are prone to substandard jagged rendering — foliage and wrought-iron fencing. This doesn’t make the game unplayable, but it means that heavy levels of antialiasing are typically required to clean the image up.

Nvidia’s TXAA method of antialiasing tends to do a good job cleaning up both jagged lines and texture shimmer, but while TXAA is supported in ACU, it’s not good enough to fix the problem altogether. In my personal opinion, 8x MSAA does a better overall job — but the performance hit from enabling it is enormous.


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