Evaluating today’s latest graphics cards can be a difficult, time-consuming process. There’s a lot that goes into a graphics card, no one metric can be used to determine the performance of a given product: the number of pixel/vertex shaders, clock speeds, memory subsystem, etc all share a symbiotic relationship. In other words, all the components within the GPU rely on each other greatly, no one component alone can be used to judge or even guesstimate the final performance of the product.
Performance isn’t the only aspect that’s used for measuring the success of a graphics card though. Equally important is the image quality of the graphics card. It’s here where things can get tricky very quickly, as judging image quality can be very subjective. What looks terrible to one person, may not be noticed by a second person; what looks “great!” or “excellent!” to one may only look “good” to another. Often times, there isn’t a very fine line separating the two, it’s more like a very subtle marker with no defined boundaries.
Today we’re going to tackle the image quality (IQ) offered by today’s latest graphics cards from ATI and NVIDIA. We’re going to do things a little different this time around though and offer more than just screenshots to compare IQ. We’re doing this because we want to take a closer look at one recurring topic that continues to come up from time-to-time: texture shimmering.
What is texture shimmering you ask? As a quick refresher, texture shimmering can occur when the mipmap transitions from one texture resolution to the next. If the transitions are harsh, the lower quality mipmap levels can stand out pretty dramatically; this sometimes causes a shimmering or flickering effect to the eye. In some extreme cases, you’ll practically see a line ahead of you marking the spot between these transitions. Ideally the higher detail textures should blend well with the lower detail textures and the end user shouldn’t notice a thing, but unfortunately this hasn’t always been the case.
In any case, going back to our original point, what we’ve found with texture shimmering is that it can be highly variable. You may never see it in one level of a game, and then in the next it’s impossible to miss it. In general texture shimmering is harder to spot in dark areas, and easiest to spot in bright, outdoor areas with long, flat surfaces. In this scenario texture shimmering can be very easy to spot, as textures on the ground in front of you are literally flickering before your eyes.
What makes texture shimmering really tricky though is that it can sometimes be incredibly difficult to spot in a static screenshot, and static screenshots are the #1 tool used by hardware reviewers to judge image quality. It’s easier to spot when you’re up and running in motion. Because of this, we’re going to rely primarily on videos, rather than screenshots, to spot texture shimmering.