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Review: Viable alternative to HD 5870 cards
Today we’ll be talking about Point of View’s GTX 470, a card that by now certainly needs no introduction. Both the GTX 470 and GTX 480 are aimed at high end market and are the HD 5800 series’ direct competitors. Nvidia launched the GTX 470 and 480 more than a month ago, and the cards are based on the largest and fastest Fermi GPU.
We expected the GTX 480 to get the full version of the GF100 GPU but Nvidia thought differently and the GF100 ended up with one disabled Streaming Multiprocessor (SM). This means that out of 512 available stream processors (16 SM x 32 cores) or CUDA cores as Nvidia likes to call them, the GTX 480 lacks 32 to reach the full number. Going downstream to the GTX 470, this card has two disabled SMs and 448 stream processors in total. Naturally, this raises questions of what happened to the full version of GF100, but at this point we can only speculate.
The GF100 is a complex chip that’s made of four Graphics Processing Clusters, four Raster Engines, six memory controllers, six ROP clusters and, as we’ve said before, 16 SMs. We’re not sure of exactly which SMs are disabled on the GTX, but we do know that the GTX 470 also comes without one ROP cluster containing 8 ROPs. At the same time, this means that the GTX 470’s memory bus is 320 bit, rather than 384-bit like on the GTX 480, which comes with all available ROP clusters. Each individual ROP cluster is assigned with one 64-bit memory controller.
In order to make the performance difference evident, the usual practice is to lower operating clocks. This is the case with the GTX 470 where the GPU runs at 607MHz, compared to the GTX 480’s 701MHz. Stream processors on the GTX 400 cards run at 1401MHz and 1215MHz for the GTX 480 and GTX 470, respectively.
The memory on the GTX 470 runs at 837MHz (3348MHz effectively). Coupled with the 320-bit memory bus, the card’s bandwidth totals at 133.9 GB/s
Nvidia opted on using GDDR5 memory, but the company did run into some problems with the speed. We see that the memory is clocked lower than on AMD’s high-end cards, but AMD uses 256-bit memory bus. As a result, the HD 5870 scores 153.6 GB/s with GDDR5 memory clocked at 4800MHz, whereas the GTX 480 (384-bit memory bus) is capable of 177.4 GB/s despite featuring memory clocked at 3696MHz.
Point of View’s GTX 470 comes with 1280 MB of GDDR5 memory while the faster, GTX 480 packs 1536MB.
The GF100 is a fast and powerful graphics processor, but cooling it on GTX 400 cards has proven to be quite tricky. Nvidia uses dual-slot cooling on both cards and while it does get the job done, both cards get pretty loud. The GTX 480’s TDP stands at 250W and the GTX 470’s at 215W. Idle consumption for the GTX 480 and 470 is 47W and 33W, respectively.
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