Sapphire Toxic HD4850 Reviewccokeman -
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The Sapphire Toxic HD4850 is PCI-E 2.0 compliant, and supports DirectX 10.1 and Shader Model 4.1. The installation of the aftermarket Zalman cooler means that this card takes up two slots on the motherboard while only physically interfacing with one PCI-E x16 slot. Clock speeds for this little bit of evil are 675MHz on the 55nm GPU core and 1150MHz on the 512MB GDDR3 memory. Both are 50MHz+ increases over the stock clock speeds.
The business end of the Toxic HD4850 contains two DVI ports and one HD-out port. The two DVI ports are Dual-Link capable, and are also able to be used for an HDMI-out signal with the supplied adapter. The rear of the Toxic houses the power circuits which are covered with a large aluminum sink to dissipate the heat from these components. The Toxic HD4850 uses a single 6-pin PCI-E power connection. This card is CrossFireX capable and should provide a nice boost running two of these cards in Crossfire mode. There are two bridge connections, although only one is needed for a two card CrossFire setup.
The heatsink used on the Sapphire Toxic HD4850 is manufactured by Zalman, and is designed to offer better cooling and less noise than a stock cooler - both things I can appreciate. With this additional cooling capacity should come additional performance. The base is mirror-polished to provide a better interface with the GPU core. The blue fan sadly does not light up, but that would not make any contribution to the cooling performance anyhow. The fan blows down over the individual RAMsinks to provide additional cooling that the reference design lacks. With that large block of copper, any heat discharged by the core will heatstroke the components, and end your overclocking adventures a little early. I'm glad to see Sapphire pick a tried and true cooling solution.
So just what's under the Zalman cooler? The RV770 core of course. The RV770PRO core is built on a 55nm process with 965 million transistors, 800 unified shader cores and is clocked at 675MHz. There's 512MB of GDDR3 memory running through a 256-bit bus clocked at 1150MHz. The Samsung memory is rated at a maximum frequency of 1200MHz, which was reached and surpassed!