Radeon HD 4870 @ HD 4890 (850/1.950 MHz) [Source: view picture gallery]
Radeon HD 4890 (850/1.950 MHz) [Source: view picture gallery]
AMD mentions slight internal improvements on the RV790. We check their effect in all the benchmarks on the next pages. In order to do so, we overclocked a HD 4870/1G (750/900 MHz)to the frequencies of the HD 4890 (850/975 MHz). In the benchmark charts those results are clearly labeled as "HD 4870 @ HD 4890”. The interesting result: The HD 4890 is, on average, slower than the overclocked 4870. We estimate that on the 4890 GDDR5 memory with slightly higher latencies is used which has a bigger effect than the internal face lifting. This impression was backed up when we had a HD 4890 run at the HD 4870 frequencies.
In addition to the game benchmarks on the next pages we have results from 3DMark 06. As you can see the GPU related results (MT Fill Rate, Vertex Shader etc.) don't differ much. But when the bandwidth is regarded, which is important for the Shader Particles and the SM3 test, the HD 4870 is always in front - no matter if a HD 4890 is running as a HD 4870 or the other way around.
Radeon HD 4870 (750/1.800 MHz) [Source: view picture gallery]
Radeon HD 4890 @ HD 4870 (750/1.800 MHz) [Source: view picture gallery]