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Written by Nebojsa Todorovic
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Thursday, 22 November 2007 |
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Page 2 of 4 One could say that AMD finally got bored with dragging its offer and decided to finally do some decent work with the new models. Here we have a completely new card, destined to impress both the press and the market. The R670 GPU is really an impressive piece of work and that is something that must be stated at the very beginning. The architecture plans were based on the experiences with the R600, with significant new changes. First of all, the chip was manufactured in the 55 nm process – the first GPU manufactured in such tiny lithography.
This made it possible for 666 million transistors to be placed on a surface less than half the previous size. The R600 had a die-size of pretty large 400 mm², whereas the R670 takes up only 192 mm². This is truly something to be proud of, and we feel we must congratulate AMD on this, since doubling the density on the die in one generation time is an immense success. This automatically means that the R670 will consume very little power. Other characteristics are similar to those on the R600. First of all, the number of stream processors is the same – 320, and the same goes for the TMU number.
Since the chip is smaller and consumes drastically less power, the thermal characteristics are much better, so the clocks were increased as well. As far as heating is concerned, we believe that many a user will hail the fact that the cooling profile on the HD 3850 is a single-slot solution. The models based on the R670 will (at least initially) be HD 3850 and HD 3870. As the majority of the article will be concerning the HD 3850, we will give you some basic info about the HD 3870 first. The stronger of the two has higher clock values and a different type of memory – that is all there is to. Both cards have a 256-bit bus (currently the optimal one), and the HD 3870 uses GDDR4 memory set to 2.4 GHz.
The GPU speed is 775 MHz. As these are quite extreme values, the advancement AMD has made is clear here. Also, the R670 is the first GPU to support DirectX 10.1, but we will probably be waiting a while before this proves its value, as hardware manufacturers are a long way ahead of software companies, primarily game developers. The new generation of AMD cards also brings support for PCI-E 2.0 and CrossFire X technology (linking up to four cards in a row). The new models also possess DualLink DVI, which enables HD material playback in resolutions up to 2560x1560, along with the 5.1 sound reproduction via the HDMI interface. All of the above is sort of overshadowed, so to speak, when you take into consideration that the price of these cards will be around 160€ for the HD 3850 with 256 MB of VRAM, a little more for the 512 MB version, and 220€ for the HD 3870!
This is a model we received directly from AMD. Even at first glance it is obvious that this is a carefully designed card. The cooling profile is similar to that of the HD 2600XT card. Still, the improvements are obvious. Firstly, the fan is larger in diameter and the fins are bigger as well, which contributes to efficiency while reducing noise. Further on, the cooling grid is still made of copper, but it is now far denser than before. Finally, there is now a curve at the exhaust part of the cooling system, so that the air is now ejected somewhere instead of anywhere as on the HD 2600XT.
All in all, the cooling system has been maximally perfected while retaining the single slot form, which is certainly for every commendation, considering the complexity of this card compared to the previous series. The card requires additional power via a 6-pin connector, but only on PCI-E 1.0 boards, as the total power consumption of the new card is only 95 W, and PCI-E 2.0 boards can provide 150 W of power just through the PCI-E slot. The clocks were as AMD specified: 668 MHz for the GPU and 1800 MHz for the memory. The 256 MB of memory have a response time of 1.1 ns.
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