Sapphire Radeon HD 4890 1GB Review

by Michael "SKYMTL" Hoenig     |     April 2, 2009

HD 4890 1GB: The Specifications

When we take a step back from the pomp surrounding the launch of a new card and actually take a look at the HD 4890’s specifications when compared next to a stock HD 4870 1GB, a few things jump right out at us. First of all, since this card is based on a slightly modified version of the RV770 core found in the HD 4870, nothing has changed in the way of Stream processors (shader units), texture units or rendering pipelines.

HD 4890 & GTX 275

In addition, as TSMC’s 55nm manufacturing process has matured, ATI has been able to make minor modifications to the RV770 core in order to warrant its new designation as the RV790. Along with the possibility of higher clock speeds, the overall efficiency of the core (both rendering and power consumption-wise) has been increased which should mean better performance clock-for-clock than the older RV770. Also, as companies have begun pushing forward GDDR5, clock speeds have been on an upswing ever since the release of the original HD 4870. Where 4Ghz modules used to push the technology to its brink, we are now seeing the first signs of 5Ghz and higher ICs making their way into the market. ATI has benefited from this since they will be able to use higher spec’d memory which consumes about the same amount of power as older ICs. In this card they have stuck to the cookie-cutter specs but in the future expect some interesting evolutions through overclocked versions of the HD 4890.

Through those natural progressions of technology, ATI has now been able significantly increase the stock speeds of their HD 4870 to make their HD 4890. Gone is the 750Mhz core; it is now replaced by a blisteringly-fast RV790 core operating at 850Mhz with the ability to clock up to and possibly past the 1Ghz mark. If that isn’t enough to get you frothing at the mouth, the memory speeds have also seen a good 400Mhz bump in speeds up to 3900Mhz. ATI hasn’t mentioned what the upper limit on the GDDR5 is on the HD 4890 but we are anxious to find out.

Overclocked versions of this card are also on the horizon and may even be available on launch day. As you will see in the performance testing, higher clocks could lead to some very interesting performance numbers versus the competition.

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