The GTX 460 is the latest addition to Nvidia’s DirectX 11 well-matched range of graphics cards. Aimed directly at the mid-range of the market, it should be a great buy for those looking for a honest amount. Nvidia has finally released a card based on a brand new chip, designed from the ground up to be smaller and less powerful but that should deliver in terms of all the other aspects of a graphics card; heat, power consumption, noise, and pricing. That card is the GTX 460 and the chip it’s based on is dubbed the GF104.
Nvidia’s first set of DirectX 11 graphics cards didn’t do well. They were all based on a new architecture called Fermi and used a new chip based on that design, the GF100, that on paper looked very impressive. Heat, power consumption, and primarily manufacturing problems plagued the GTX 480 and GTX 470 and neither delivered the performance to justify these compromises.
So it came up with something new, and this time also impressive. GF100 contains 512 Stream Processors, or Cuda cores as Nvidia likes to call them, which are the main processing units of the chip. These are split up into sets of 32, in what’s called a Streaming Multiprocessor (SM). This also adds four texture units, some cache, thread schedulers, and the polymorph engine, which handles geometry processes like tesselation.
Four of these SMs are then clustered together to form a General Processing Cluster, which basically just adds a raster engine. Finally, four of these GPCs are added together along with further thread scheduling components, the host interface, memory controllers, ROPs and 512KB of L2 cache. The result is one enormous and hot chip that contains whopping 3.1bn transistors. However, due to production problems, the GTX 480, has one of the SMs disabled so you actually get 480 SPs, 15 SMs, and 60 texture units.
For GF104, all the basic building blocks are very similar, but their proportions have been tweaked. So, you get 384 SPs, split up between just eight SMs, giving you 48 SPs per SM. To deal with these extra SPs, each SM also has double the number of texture units. Each SP has also had a second dispatch port added for more efficient thread handling. Finishing things off, GF104 has 32 ROPs, split up into four sections.
There will also be two versions of the GTX 460, one with 1GB of RAM and one with 768MB. The latter also has a reduced memory sub-system with the amount of L2 cache dropping from 512KB to 384KB and the number of ROPs from 32 to 24. We shall be taking a look at this version of the card shortly. Today, then, we’re looking at the Zotac GeForce GTX 460 1GB, which uses a reference design and runs at standard clock speeds.
The card we’re looking at uses a radial fan sucking air in from the front of the card, blowing it across the heatsink and out the back of the card. Others use axial fans blowing straight down onto the card. Generally we prefer the approach Zotac has taken as these coolers exhaust the hot air straight out of your PC case. However, this particular design isn’t the quietest we’ve encountered with it idling at 48dB and rising to 53dB under load.
In contrast the stock (i.e. Nvidia designed) cooler on the GTX 470 runs at 40dB/50dB, while ATI’s competing cards also run at sub 40dB when idling. The Zotac card isn’t loud enough to disturb you if you’re just sitting working with some music on. Otherwise, the Zotac design seems fine. It’s 218mm long, which is plenty short enough to fit in most cases, and you get oodles of video outputs, with two DVI, an HDMI and a DisplayPort on offer more than any other card we’ve seen from Nvidia.
Tags: gf100, gf104, gpcs, Graphics Card, Graphics Cards, Gtx, gtx 460, gtx 470, gtx 480, multiprocessor, Nvidia's DirectX 11, stream processors