Sapphire HD4870 X2 Reviewccokeman - August 11, 2008
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The one thing that comes to mind as soon as you look at this card is how similar it looks to the HD 3870X2, but looks are where the similarities end. The Sapphire HD 4870X2 is PCI-E 2.0 compliant, supports DirectX 10.1, Shader Model 4.1, Unified Video Decoder, and 7.1 surround sound. This HD 4870X2 features a clock speed of 750MHz on the 55nm RV770 GPU cores, and 900MHz on the 2GB of GDDR5 memory running on a 256-bit bus. So just what else does the HD 4870X2 bring to the table? How about 2.4 teraflops of computing power, almost two billion transistors, 1600 streaming processors, and almost twice the memory bandwidth of the HD 3870X2. How bout that for some muscle? This card is big, and measures 10.75 inches long from the expansion slot bracket to the end of the black PCB. Making sure you have a case and power supply that can handle the size and power requirements is a must. ATI/AMD even has a list of certified power supplies and chassis that you can choose to use for your build. This card uses a dual-slot cooling solution that physically takes up two expansion slots. To use the HD 4870X2 in a CrossFireX configuration, you will need a motherboard that has two PCI-E x16 slots.
The Sapphire HD 4870X2 has three display ports for every option you might need. There are two Dual-Link DVI ports which can support multiple monitors from one card, and a Video out port which provides component and S-Video options using the supplied adapters. Unlike the HD 4870, which uses two 6-pin power ports, the HD 4870X2 uses both a 6-pin and an 8-pin PCI-E power plug to provide the necessary juice to run this beast. The power plugs are on the top edge of the card near the rear, one on each side of the blower fan. The HD 4870X2 also eliminates one of the CrossFire bridge connections since you only need one other card to achieve a multi-card CrossFireX setup, instead of three or more.
The HD 4870X2 uses a dual-slot cooler design to maximize the airflow and lower the temperatures of the components. This leads to better performance and a longer life span of the card. The cooler designed for the HD 4870X2 is a multi-part design; there are two copper heatsinks used to cool the GPU cores. The airflow through the shroud blows through both heatsinks. This will lead to the second GPU core always running warmer than the first. The rear of the card is covered by a thin aluminum heatsink that has the sole responsibility of cooling the Hynix memory modules on the back side of the card. The last part houses the two GPU heatsinks and is attached to the shroud. This aluminum plate contacts the memory, as well as many parts of the power circuitry, to reduce the temperatures of these components. In addition to the plate, there are additional cooling "pins" that are used to create more surface area to help with the cooling of the card. All of the air blown through the heatsink assembly is pushed out the back of the chassis, unlike the HD 4850 series of cards.
With the heatsink assembly removed, we can get a better look at what makes this beast a winner. Unlike single GPU setups, the HD 4870X2 uses a three chip design. There are two 55nm RV770 GPU cores and a PCI Express bridge chip. The Bridge chip is made by PLX, and is a second revision chip which supports PCI Express 2.0 unlike the one in the HD 3870X2 cards which used PCI Express 1.0. The HD 4870X2 has the same clock speeds as the HD 4870 for the CPU and memory - at 750MHz and 900MHz (3600MHz effective) respectively. The difference with the HD 4870X2 is that there's a total of 2GB GDDR5 (1GB for each GPU) instead of the 512MB that the HD 4870 has. Also, the HD 4870X2 uses two 256-bit memory interfaces instead of just one, since each core has its own memory. The memory for the Sapphire HD 4870X2 is made by Hynix, uses modules listed as H5GQ1H24MJR TOC, and are rated for 4.0GB/sec.
Now that you have seen the card from top to bottom and down to the bare bones, let's see what it can do.