Rumour: Mid-range Fermi details emerge

Now that the official GeForce GTX 480 shindig is out of the way, the tech grapevine has already sprung into action with juicy gossip about the next chips based on the architecture.

In particular, rumoured details have started to emerge about a mid-range chip called GF104.

The German tech-heads over at 3D Center (Google translation) have the full skinny, which they say they "collected from a trusted source". The site bravely claims that the information is "not speculation or conjecture, but real information". We’ll have to take their word for that, but the information appears to be in line with expectations.

According to the site, the Fermi-based GF104 supports up to 256 stream processors. This is half the theoretical maximum that the GF100 architecture can support, although the recently-launched GeForce GTX 480 only has 480 stream processors. The site also claims that the GF104 will feature a 256-bit memory interface that can support GDDR5 memory, although we suspect that it will be partnered with GDDR3 memory as well.

Interestingly, however, the site claims that GF104 will feature 64 texture units, which would be quite surprising given that the GTX 480 only has 60. However, it’s worth bearing in mind that the original GF100 chip with 512 stream processors was also supposed to have 64 texture units, but four of them got knocked off along with 32 stream processors.

Meanwhile, the site puts the ROP (render output) count at 32, compared with 48 on the GTX 480. The GF104 apparently won’t support double precision either, but that’s unsurprising given that double precision is only really used in large-scale GPGPU computing.

There’s no confirmation on clock speeds yet, but the site confidently says that the chip will support a GPU core clock of 725MHz, stream processor clock of 1.5GHz and a memory clock speed of 1.8GHz. The prediction is that there will be a couple of variations (possibly called the GTS 450 and 440), which will have different clock speeds and will be aimed at slightly different the markets. 3D Center predicts that the cards will be positioned against the Radeon HD 5830 and 5770 respectively.

As with anything on the gossip circuit, bear in mind that none of this is official. We asked Nvidia whether there was any truth in the rumours, but the company unsurprisingly declined to comment. Either way, it’s unlikely that we’ll see the new chips in the very near future. Last month, Nvidia’s CEO Jen-Hsun Huang revealed that “Q2 is going to be the quarter when Fermi is hitting the full stride.” In this case, Q2 refers to the second quarter of fiscal year 2011, which will span the May to July period of 2010.