Unofficial HD4870 benchmarks

On the to us relatively unknown website Bilgiustam benchmarkscores have appeared of AMD's new HD4870 graphics card, that is about to replace the HD38700 series. The benchmarks have been performed on a system with a P5E3 (X38) ASUS motherboard and a fast Intel QX9650 quadcore processor. There were two 1 GB DDR3 memory modules by OCZ used, running at a speed of 1333MHz. 

The 9800GX2 graphics card was running at it's reference speed of 600, 1500 and 200MHz for respectively the core, shaders and GDDR3 memory. The HD4870 video chip was clocked at 800 MHz with the GDDR5 memory at 1700 MHz (3400 MHz effectively). 

The benchmarks show that AMD's latest graphics card takes the lead over the GeForce 9800GX2. The HD4870 gets almost 33% more points in the entire test and even with SM2.0 and SM3.0 the scores of the 9800GX2 are only about 75% of the HD4870. In Crysis the HD4870 seeems a lot faster than nVidia's dual-gpu card as well, however the difference gets significantly smaller when the resolution is increased from 1280x1024 to 1600x1200. 

If these scores are legit it means AMD has done very well to compete with nVidia's 'new' 9800 series.  However, when we take a critical look to these scores it leaves us baffled. The RV770, being the base of the HD4870, would only have 480 or 640 shaders as far as we know, and the amount of TMU's would raise from 16 to either 24 or 32. In the most ideal situation the HD4870 would be twice as fast as the HD3870, which scores worse than a single nVidia G92 with 128 shaders. The 9800GX2 however, consists of two G92 chips, and still the HD4870 manages to take the lead easily, while the clockspeed isn't much higher than the RV670's.

The only remaining variable is the memory bandwidth, which is much bigger with the RV770 compared to it's predecessor, the RV670. However, it is doubtful whether this will have a significant influence on the performance.

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