Nvidia GeForce GTX 460
Developing its GF104, Nvidia tried to take into account all the mistakes it had made with the G200 and GF100. As a result, the new chip comes out rather compact with a transistor count of 1.95 billion and a die size of 320 square millimeters. This is comparable to AMD’s RV870 Cypress with its 334 square millimeters and 2.15 billion transistors. Of course, the GF104 is a full-featured representative of the Fermi architecture and does not differ from the GF100 fundamentally. However, there are a few minor differences, particularly in the design of the execution modules.
While the GF100 consists of four graphics processing clusters each of which includes 4 multiprocessors with 32 stream cores in each, the GF104 is different. Each of its two GPCs still contains four multiprocessors but the latter are configured differently. Now each of them consists of 48 stream cores, for a total of 384 ALUs and 65 texture-mapping units. Considering the scalar architecture, the new chip is 1.6 times as good as its predecessor G200 in terms of computing resources. However, Nvidia says the chip includes only 336 stream processors and 56 TMUs. Why?
The fact is one of the eight multiprocessors of the GF104 chip is inactive, just as in the GF100 chip (even in its maximum GeForce GTX 480 configuration). Nvidia must have done everything necessary to release the new core as soon as possible and achieve an acceptable yield of chips capable of working at rather high frequencies, and this is one such measure. As soon as the tech process gets polished off, the inactive multiprocessor can be turned on to make the GF104 a really dangerous rival to the RV870 Cypress. The new chip, working at 675/1350 MHz and having 336 ALUs and 56 TMUs, is quite competitive even in its current form, though. Another difference of the GF104 from the GF100 is that the amount of L2 cache memory is reduced from 768 to 512 kilobytes. This shouldn’t have a fatal effect on its performance, yet we should keep this fact in mind.
It must also be noted that the GF104 is Nvidia’s first new-generation solution to support Protected Audio Path. It is thus able to work with the multichannel HD audio formats Dolby TrueHD and DTS-HD Master Audio. This used to be a prerogative of the ATI Radeon HD 5000 series but Nvidia has finally caught up with its opponent in terms of multimedia capabilities. RV870-based solutions have got a worthy rival at last.
July 12, 2010, the new core was announced officially. Besides, Nvidia unveiled two GeForce GTX 460 series products we will discuss in the next section.