Overclocked 6870 has lower frame rate than Stock frequencies???


Jul 15, 2010

I am baffled as to why my Gigabyte Radeon HD 6870 1GB OC Edition performs poorly when overclocked with AMD Overdrive (in Catalyst 11.8). The stock frequencies of this card are 915/4200 and I overclocked them to 925/4240 by using sliders. When running the benchmark in FarCry2 at MAX settings with its built in tool, I get a lower average and max FPS with overclocked frequencies. Temps are fine. Details below.

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System Specs:

CPU: intel CORE i5-2500k @STOCK
MB: Gigabyte Z68A-D3-B3
GPU: Gigabyte Radeon HD 6870 1GB OC
Monitor: 1920x1080 / 60hz
OS: Windows 7 x64

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Benchmark Results:

Game: Far Cry 2
In-Game Settings: Settings: Demo(Ranch Small), 1920x1080 (60Hz), D3D10, Fixed Time Step(No), Disable Artificial Intelligence(No), Full Screen, Anti-Aliasing(8x), VSync(No), Overall Quality(Ultra High), Vegetation(Very High), Shading(Ultra High), Terrain(Ultra High), Geometry(Ultra High), Post FX(High), Texture(Ultra High), Shadow(Ultra High), Ambient(High), Hdr(Yes), Bloom(Yes), Fire(Very High), Physics(Very High), RealTrees(Very High)

Results: STOCK FREQUENCIES (915/4200)

Average Framerate: 65.34
Max. Framerate: 142.06
Min. Framerate: 50.63


Average Framerate: 63.32
Max. Framerate: 115.55
Min. Framerate: 49.27

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So basically, you already oc your card to the point of artifact. But instead of having artifact showing up, you now have the error correction which slows down the performance.

I really don't see why you what to oc your card further. Your card is already oc at the factory, so there isn't much headroom. Reference clock for 6870 is 900/1050.