PowerColor HD 4890 Reviewccokeman -
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The PowerColor HD 4890 is designed for use in a 16x PCIe slot and uses what is considered a dual slot cooling solution. This means it will take up the space of two expansion slots, while physically only using one 16x slot. The card is a reference design card from ATI. The HD 4890 uses the R790XT core and is built using a 55nm process. The core features the same general specifications as the R770 core, but at much higher clock speeds of 855MHz on the core and 975 on the 1GB of GDDR5 memory. By looking through the heatsink duct, you can see the three heatpipes going into the fin array from the contact plate.
Connectivity is much the same as you would find on the HD 4870, with 2 Dual link capable DVI ports and an HDTV outlet that can be used with either of the supplied adapters. The rear of the card is where the power connections are installed again, much like the HD 4870. There are two six-pin PCIe power connections instead of an 8 pin and 6 pin. The HD 4890 can be used in a CrossfireX configuration. There are two bridge connections on the card to facilitate the multiple connections needed when more than two cards are used.
The PowerColor HD 4890 uses the reference cooling solution to discharge the heat generated by the GPU and memory. The fan used is a blow-through design that ATI has used for quite some time now and the noise generated by the fan is nothing short of loud. It was easily the loudest thing in the chassis. The heatsink is a made up of a copper base with three heatpipes running to an aluminum fin array. The base of the heatsink is stepped, so that contact is directly on the core and not anything else. The memory is cooled by a large passive heatsink that covers the GDDR5 memory, as well as the mosfets for the power circuit.
The heart of the PowerColor HD 4890 is the R790XT GPU core. This GPU is built on a 55nm process and features close to a billion transistors, 800 Unified shader processors running at 850MHz - 100 MHz faster than the clock speeds delivered by the HD 4870. The HD 4890 is supplied with 1GB of GDDR5 memory made by Quimonda and is rated for operation at 1000MHz. The memory on the HD 4890 is clocked at 975MHz and runs through a 256bit bus. The clock speed is almost at the rated speed of the memory. All of the power circuitry is located toward the back end of the PCB.
Now we know a little bit more about the HD 4890, you can see it looks like a really well binned HD 4870. Could it be just a core re-name, or is it really something different?