The first GF104-based graphics card, the GeForce GTX 460, will come in two flavors. Both will use a scaled-back GF104 chip with one of its eight SMs disabled, leaving a total of 336 ALUs and 56 texels per clock of filtering capacity. The two share common clock speeds: a 675MHz core, 1350MHz shader ALUs, and 900MHz (3600 MT/s) GDDR5 memory.
The tastier flavor of the GTX 460 is the 1GB version, which has 32 ROPs, 512KB of L2 cache, and a 256-bit path to memory. The card's max power requirement, or TDP, is 160W, and it requires two 6-pin auxiliary power inputs. Nvidia says this card will sell for $229.
The more accessible version is the 768MB card. Since it's down one memory interface/ROP partition, it has 24 ROPs, a 192-bit memory path, and 384KB of L2 cache. This version has a slightly lower 150W TDP, but it also requires dual 6-pin power inputs. Accepting this card's smaller memory size, lower bandwidth, lesser ROP throughput, and smaller cache will save you 30 bucks off the list price, since it should sell for $199.
We'd really prefer that Nvidia had used its magical powers of branding here to set a bright and shining line between these two products. You're giving up a lot more than 256MB of memory by going with the 768MB version, and we understand that "GeForce GTX 455" is available. You know there will be folks who pick up a GTX 460 768MB without realizing it's a lesser product. The GTX 460 768MB isn't bad, but such confusion isn't good for consumers.
Pictured above are a couple of GeForce GTX 460 cards. The one on the left is Nvidia's reference design, and the one of the right comes from Zotac. (The reference card is a 768MB version, but the reference 1GB card looks just the same.) Nvidia's rendition of the GTX 460 has a pair of DVI outputs and a mini-HDMI connector. Zotac's offering is simply better, with full-sized HDMI and DisplayPort outputs, along with dual DVI ports.
Here's a surprise: the GTX 460 supports bitstream audio over HDMI for Dolby True HD and DTS-HD Master Audio. I believe that's a first for Nvidia graphics cards, and it should make the GTX 460 a nice candidate for an HTPC system.
Notice that these two cards have different coolers. The reference design uses a fan that has a Zalman-esque heatsink beneath, while Zotac's card employs a blower. Nvidia expects some board vendors to use its reference cooler, but obviously, others will not. We have no problem in theory with a blower like the one Zotac uses; lots of high-end graphics move air efficiently and quietly with blowers. However, the reference cards' fans are very noticeablyand measurablyquieter. We think it's possible this particular blower on our Zotac card may have a bad bearing or something, because it did tend to rattle a bit at times, but we only have the one card to judge.
The GTX 460 sports a very compact board design, with a total length of only 8.25". As you can see from the pictures above, that's quite a bit shorter than some cards in this price class, most notably the Radeon HD 5830. Since AMD didn't produce a reference PCB design for the 5830, most manufacturers have based their cards on the Radeon HD 5870 PCB. That makes the 5830 a relatively lengthy card for this class, and it could present fit problems in smaller cases. Even though it's based on a much larger GPU, the GTX 460 is no longer than the Radeon HD 5770.