Intel is the leader of the GPU market
The number one company on the GPU market seems to be Intel, which registered a total of 44.67 million units shipped during the second qurter of this year, going up with almost 10 percent on-year, from the 37.6 percent registered in the second quarter of 2007 to the 47.3 percent in shipments the company accounted for during the second quarter of 2008.
Intel doesn’t have a discrete graphics offer, but still manages to dominate the graphics cards market, while the three-month period registered market share drops for both AMD and Nvidia. The market share went down for Nvidia from 32.5 percent to 31.4 percent on-year, while for the AMD, it dropped from 19.3 percent to 18.1 percent. 
AMD is preparing the launch of its RV770-powered Radeon HD 4800 series cards, which may come as a serious impact on the industry. The 4870X2 card should set the difference on the market.
A serious war on the GPU market was announced earlier this year between AMD and Nvidia. It seems that AMD struggles to make its ATI graphics division more profitable and spends a lot on research of new technologies, as the dual GPU graphics cards are. Nvidia, on the other hand, faces some problems with its mobile video chips, but still manages to bring novelties like the porting of physics to the GPU. Intel promises to enter the war sometime in the 2009-2010 time frame, when its Larrabee video computing architecture is launched.