The GeForce GTX 295, which uses two graphics chips working together in a single package, was nVidia's first commercially available graphics card to use chips built on a 55nm manufacturing process. Previous cards from nVidia had all been built using a 65nm process so in relative terms they were more power hungry, ran hotter, and were more costly to produce. So, all told, this new manufacturing process was quite an exciting proposition.
However, the GTX 295 costs around £500 and is somewhat over powered for many of us - not to mention the whole 'SLI on a card' thing can still be somewhat temperamental. So, what we've really been waiting for is for nVidia to release cards based on chips built using the same smaller manufacturing process but with just one chip per card. In other words, we've been waiting for the card I'm looking at today, the GTX 285.
As the name suggests, this is a direct follow up to the GTX 280 that launched last June and so bares a striking resemblance in many ways. For a start the chip still uses 240 stream processors split up into 10 stream processing clusters, 80 texture units, and 32 ROPs communicating with 1,024MB GDDR3 memory across a 512-bit interface. The card itself is also the same length and from certain angles looks identical. Looks can be deceiving though and there are certainly a notable number of changes.
First things first, the clock speeds have improved. The core clock has gone from 602MHz to 642MHz while the stream processor clock is now 1,476MHz, up from 1,296MHz, and the memory ticks along at 2,484MHz, an increase of 270MHz. All told these equate to an average increase of about 11 per cent, which isn't exactly ground breaking but when you consider the quoted board power of the GTX 285 is actually 183W, as compared to the 236W of the GTX280, you can see it's not just a performance benefit that you'll get from buying one of these cards.
The board design has also changed quite considerably though outwardly these changes are at best subtle. In line with the reduction in power consumption, this card now only requires two six-pin PCI-Express power connectors rather than the six- and eight-pin connectors needed by the GTX 280. The power regulation circuitry has also been tweaked, particularly with a mind to reducing the peculiar whistling noises that plagued the GTX 280. This occurred only when the card was used with certain power supplies (actually most, in our experience) and at certain load levels (primarily just when turning the PC on) and were a result of electrical resonance between the card and power supply, creating a high-pitched whistling noise. According to some reports these fixes haven't fully resolved the issue but at least on the two power supplies we've tested it on, the problem has disappeared.
Other changes to the board include the memory chips. Whereas on the GTX 280 the chips were mounted both on the back and front of the card (hence the protective backing on that card) all the chips are now on the front of the GTX 285. This means they are covered by the active cooler that also cools the main GPU chip, which could potentially lead to better cooling and better overclocking of the memory. It does mean we lose the protective backing though.
One thing that hasn't changed is nVidia's display controller which still doesn't natively support DisplayPort so board partners will need to add their own DisplayPort controller chips to enable this connection. What you do get, though, is two dual-link DVI sockets and an analogue video output that supports S-Video, composite, and component outputs either natively or with the help of included dongles. Likewise, HDMI is supported via a DVI-to-HDMI dongle and there's an audio connection next to the power sockets to enable audio pass-through.
One final point about the card's physical design is its inclusion of the obligatory SLI connectors that appear in their usual location along the top edge of the PCB. The card can be used in dual- or triple- SLI configurations, both of which are scenarios we hope to test soon. For now, though, we'll be doing just single card testing.