Video Overclocking and Bottlenecks

Video = CPU?

One of the things that Creative stressed was how similar video overclocking was to the same practice for CPUs. 3D accelerator cards are quickly becoming as complex as processors in terms of gate complexity and manufacturing, and 3D now has to carry up to 32MB of RAM on the PCB. This causes an interesting problem.

When overclocking was first established, heat was the primary cause for worry. As manufacturing processes and yields improved, suddenly power consumption became a big deal, resulting in the current trend of variable voltage motherboards.

How does that add up?

In some ways, 3D accelerators are also reaching that point. Before, RAM speed, PCB manufacturing, and a number of issues stood as bottlenecks in the quest to overclock. Now, with increasing amounts of RAM on board, with power-hungry 3D processors, power consumption may become a limiting factor for video overclocking. The AGP bus may not be able to deliver the juice needed by the card for stable overclocked frequencies.

In fact, Creative speculates that next-generation cards with 64MB on board may need up to 15 watts of power, going so far as to suggest situations in which a separate power supply would be needed just for the video subsystem! Needless to say, that begets an entirely new set of problems, including increased thermal issues to deal with.

By the time we hit .18 um and/or 64MB for video cards (late 1999 to mid 2000), it's likely that some of today's problems will have been solved - "necessity is the mother of invention," after all. Some motherboards are already including AGP voltage adjustment, and this may just be the beginning.