And now for the numbers
Here's where the rubber meets the road: We assembled two systems, the first of which had an AMD A8-7600 APU with Radeon R7 series integrated graphics in an Asus A88X-Pro motherboard. The second system featured an Intel Core i5-4670 processor with Intel HD 4600 integrated graphics in a Gigabyte Z87X-UD5 TH motherboard. Both systems were outfitted with 16GB of memory, a Samsung 840 Pro SSD for storage, and a 1000-watt Silverstone power supply. The 64-bit version of Windows 8.1 Pro x64 was installed on both systems.
We ran a series of benchmarks — some gaming-oriented, some focused on productivity and content creation — using just the graphics processors integrated into the respective CPUs. We then installed a Radeon R9 280X video card (this particular model was from XFX) in each system and reran all the benchmarks.
As you can see from the charts (we didn't create one for every benchmark we ran), adding a discrete graphics card improved performance nearly across the board — and it wasn't only games that benefited. In PCMark 8, for instance, we ran the OpenGL-accelerated versions of the Home and Work suiters. This API leverages all of the PC's available compute resources, both its CPU and its GPU. Adding a discrete GPU to the equation boosted the system's performance on this one benchmark between 3 percent and 19 percent.
Adding a GPU had very little impact on the Cinebench multi-threaded CPU benchmark scores, but it boosted the Intel-based system's performance with the Cinebench OpenGL benchmark by a staggering 79 percent, and the AMD-based system's performance on this benchmark by 42 percent.
People often assume that casual gamers — folks who play Farmville, Angry Birds, and other "simple" games — will see no benefit from discrete graphics. But when we added a discrete GPU to each system, we saw significant performance gains with Microsoft's browser-based HTML5 benchmark, Fishbowl. This particular test is capped at 60 frames per second (the refresh rate of most monitors), and it hit that cap in three of the four tests we ran with the discrete graphics card installed. As casual games become more complex, so will their need for GPU horsepower.
Speaking of complex games, adding a discrete GPU delivered a major shot in the arm to our test systems when it came to delivering BioShock Infinite (at resolution of 1920 by 1080 pixels) and the synthetic gaming benchmark 3DMark Fire Strike.
But there is one application where adding a discrete video card did not have a significant impact: Video playback. We saw very little impact on CPU utilization while streaming both YouTube videos (HTML5) and video files encoded using the h.264 codec and placed inside MKV containers.
The bottom line is that nearly every desktop PC user can benefit from the addition of a discrete graphics processor. Video cards aren't just for gamers, but the benefits for gamers far outweigh the benefits delivered to mainstream users.
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