AMD Radeon HD 3870 X2:
Not so much time has passed since the announcement of the new Radeon HD3000 family with Radeon HD3850 and Radeon HD3870 video cards, and AMD has announced another video card. In fact, it is not so new because it is based on the two well-known and familiar RV670 chips. We wonder why AMD needed to release a dual video card - it is indeed of a complicated design and most likely heats up immensely, let alone its high power consumption.
The answer is straightforward: the reason for releasing a "dual" video card was the lack of a solution competing against NVIDIA's flagships, and the desire to gain more profits within a short time. Indeed, if AMD releases its future flagship based on the R700 graphic chip ahead of time, it may prove to be "raw", which may endanger the plans for conquering the market. Releasing of a video cards based on two chips, AMD kills two birds with one stone. First, there comes up a video card that is capable to compete against NVIDIA's top-end solutions. Secondly, this would give AMD more time to polish the future graphic processor R700. Such a move has been proven in practice because once NVIDIA stopped evolving the GeForce 7 product line and GeForce 8 was not yet there, it released GeForce 7950 GX2 based on two GPU G71 in good time and thus filled the market with a high-performance solution for a sufficient timeline.
Therefore, to all appearances, Radeon HD3870 X2 is a temporary solution which should compete against the higher-end NVIDIA video cards up to the moment the R700 chips and video cards on its base have been released. Therefore, the new video card Radeon HD3870 X2 is being positioned as a competitor to GeForce 8800 Ultra. Anyway, we'll certainly try that out, but now let's take a closer look at the novelty.
We received an engineering sample of AMD video card, so there can't be any packages, bundled items or the like. What matter is that the video card is there. As you can see, externally the video cards is very similar to Radeon HD2900XT, but it's hard to mix them up. The cause of that is not only the eyes of Ruby welcoming us with a sharp-sighted gaze and hinting that there are two processors inside (as many as the eyes?), but also the much longer board itself and the cooling system.
Will the video card fit inside a "regular" housing? Indeed, you may come across this issue, but we should give credits to AMD, since the new Radeon HD3870 has proved to be a bit shorter than the competing GeForce 8800 Ultra, which also applies to GeForce 8800GTX. So, to install the AMD's new product you would need a regular spacious housing, which is no wonder.
The imminent consequence of two video processors is the twice as many memory chips, half of which positioned on the rear side and covered with a metal radiator plate. There are 16 memory chips altogether (versus 8 in the regular Radeon HD3870/HD3850).
What attracts your attention is that there is only one CrossFire connector instead of two customary. That resulted from use of the CrossFire technology within the video card, that is, one of the connectors was used to interconnect two GPUs. Now let's dismantle the video cards and see what is hidden under the cooling system.
Our attention was drawn by the chip positioned between the two GPUs as well as the different color of radiators for their cooling. One of them is made of aluminum, but we'll talk about that later.
The chips are positioned in a somehow unusual way, with the graphic chips facing one another and placed densely enough. Such a tight and unusual layout is a result of compact layout, because of there had to be placed two video cards and a matching chip on a PCB with so confined dimensions!
The reverse side can boast 8 memory chips, and there is nothing more to look at over there.
The distinction of the dual-chip Radeon 3870 X2 from the single-chip version is the GDDR3 video memory of 1.0 ns access time, which is equivalent to 2000 MHz (1000 MHz DDR). The real frequency of the video memory operation is lower, which we'll mention later.
Now a few words on the architectural traits of Radeon 3870 X2. The major idea behind AMD's new announcement is to integrate two RV670 graphic processors on a single board via the PCI-Express switch based on the PLX PEX8547-AA25BC chip. The below figure displays its operating principle.
The PEX 8547 chip is a hardware switch with 48 PCI Express lanes, support for PCI Express Base Specification, r1.1, and is specially designed for high-speed "point-to-point" switching for high-bandwidth lines. The PEX 8547 switch is made in a compact 676-pin PBGA package and is 37.5 x 37.5 mm in dimensions. The typical power consumption of PEX 8547 does not exceed 4.9W, with the latency in switching "x16 to x16" lines lines not exceeding 110 ns. Of the 48 PCI-Express lanes supported by the switching chip, 32 lanes in the architecture of Radeon HD3870 X2 are allocated to connect to graphic chips, with the remaining 16 – to the PCI-Express x16 slot. As can be seen from the figure, the GPU can communicate between one another and with the system bus directly via a switching chip. The communication mode is full-duplex, that is, data can be exchanged in both directions simultaneously.
Therefore, according to the idea of engineers at AMD, the architecture used in developing the Radeon HD3870 X2 is able providing an up to 1.7 times higher performance gain as compared to the card based on a single chip HD3870. At the same time. positioning of all the CrossFire components on a single board should result in improved power-saving and optimum cooling of the components.
The cooling system of Radeon HD3870 X2 is made up of an aluminum housing, a fan known from Radeon HD2900XT, two radiators for cooling the GPU, made of copper and aluminum; and a red plastic housing. There is a clearance between GPU radiators and the aluminum housing, which allows for adapting to the relief of the video card thus avoiding the warp.
The aluminum radiator is positioned closer to the fan, which is no wonder because it rejects heat from the copper-made piece and it requires colder air or faster air flow. The reason why AMD used aluminum instead of copper is straightforward. The video card is heavy enough, and a copper radiator would result in a damage to the video card or the slot on the motherboard.
The processing quality is good albeit not perfect. We'll try the cooling system efficiency in action later, but now a few words on the video card's dimensions.
The brand-new card has proved much larger than Radeon HD2900XT and, therefore, Radeon HD3850 and Radeon HD3870. However, it is not a dinosaur at all!
As compared to GeForce 8800GTX, it has proved to be a bit smaller. Not bad indeed, but not every housing can fit the "little kid" by AMD.
The below table presents a summary of Radeon HD3870 X2 specifications. As you can see, the marketing people at AMD couldn't help amazing the potential customer with the overall number of streaming processors, texture units, and other "dual" specifications of Radeon HD3870 chips.
Let's sum up the specifications of Radeon HD3870 X2 declared by the manufacturer. AMD Radeon HD3870 X2 is a dual-slot CrossFireX solution with the 2? 256-bit memory interface and support for up to 1 GB of GDDR3 memory running at 2 GHz; the peak power consumption up to 196 W, and the noise level no more than 36 dBA. The card offers support for the ATI PowerPlay and is equipped with the HDTV output, two DVI interfaces with support for HDCP, as well as HDMI via an adapter. According to the idea of engineers at AMD, the architecture used in developing the Radeon HD3870 X2 is theoretically able providing an up to 1.7 times higher performance gain as compared to the card based on a single chip HD3870.
||CPU & Memory: