Well, according to John Peddie Research (JPR), not too good if you are Matrox or S3. The total market for add-in boards decreased 5.4% from last quarter. 14.0 million were shipped across the entire industry. Neither company accounted for a thousandth of that value leaving them with a maximum 7000 units shipped, best case scenario. This industry is, basically, a two horse race.

GPU suppliers, market share
  This Quarter Prev. Quarter Last Year
AMD 38.0% 35.7% 40.3%
Matrox 0.0% 0.0% 0.3%
NVIDIA 62.0% 64.3% 59.3%
S3 0.0% 0.0% 0.1%
Total 100.0% 100.0% 100.0%

Two horses unless you count the Intel Xeon Phi. While technically not a graphics processor despite hardware design, 48,000 of these coprocessors were sold, already, for the Tianhe-2 supercomputer. This is at least seven-fold more than an entire quarter for Matrox. Unfortunately JPR does not report on Intel add-in cards despite its overlap with the GPU add-in market. These numbers could get even more interesting as years progress.

As for the two big players, AMD and NVIDIA, both hold very dominant positions. Almost spiting the 750,000 unit industry decline, AMD experienced a total increase of 0.8% quarter-over-quarter. Their market share gained 2.3% as a result of this growth. NVIDIA experienced a total decrease of 8.9%.

In all, AMD has been doing better than the industry average. They are fighting the slight decline in the graphics industry while simultaneously helping GPUs hold off against larger declines in PC systems.