X-bit labs

From Extreme to Mainstream: Nvidia GeForce 8800 GT from Leadtek (page 2)

Category: Video

by Alexey Stepin , Yaroslav Lyssenko

[ 12/03/2007 | 03:09 PM ]

Nvidia G92: Architecture, Features, Innovations

Specifications

Nvidia developed a new graphics processor, codenamed G92, for use in the GeForce 8800 GT graphics card series. Let’s see what technical characteristics it is endowed with.

Click to enlarge

Click to enlarge

First of all, we should note the thinner tech process in comparison with the G80 chip (GeForce 8800 Ultra/GTX/GTS). Theoretically, this should keep the die area, power consumption and heat dissipation within reasonable limits, which is important considering the increased transistor count. The new chip surpasses both Nvidia G80 and ATI R600 from this point of view, being currently the most complex GPU in the world.

It may be partially explained by the integration of the NVIO unit, previously a standalone chip, into the G92 die as well as by the more advanced PureVideo HD video decoder and post-processor. Some general improvements on the micro-architecture level and the PCI Express 2,0 interface may have contributed to the increased number of transistors as well, yet we don’t think that all those innovations are indeed worthy of 72 million transistors. Perhaps the G92 contains more shader and texture processors than declared but some of them are just disabled for now. If so, Nvidia will be able to easily introduce new G92-based solutions with higher performance or guarantee a 100% yield of chips with the existing configuration.

The new core represents a modified G80 architecturally, the revision having concerned texture processors mostly. The G80 has two filter units per each texture address unit, which ensured a high performance with anisotropic filtering, but the G92 is configured like the G84 in this respect with two filter units for each two address units.