In terms of FSX performance, my newly added ASUS HD 6970 Direct CU II graphic card is just slightly better than my previous ASUS Matrix HD 5870. However, it does bring a better image quality and a much cooler and quiet environment to my system. Moreover, the card allows connection up to six monitors, giving me flexibility when planning for future multi-monitor system upgrade.
The Radeon driver I am using is the latest 11.11 (updated on Nov-28). Despite the new features come with the new driver, the Mipmap Detail Level option in 3D Application Settings was gone for the HD 6970. Moreover, the Wide-tent and Narrow-tent filters of Anti-Aliasing were combined into one Edge-detected filter.
After days of testing, the HD 6970 resulted in a different settings (below) than the HD 5870 even though most options remain unchanged. One particular, the new card prefers to disable the Triple buffering option that I was using all the time for AMD cards in the past (click here to see my earlier 11.8/11.9 settings).
Updated Dec-11, 2011
Also, changing the Wait for vertical refresh to Always On (previous Always Off) seems like making the display more stable even when ForceFullScreenVSync is already enabled in fsx.CFG.
Regarding overclocking, I am using Catalyst Control Center’s new AMD Overdrive feature to raise the GPU clock from 890 MHz to 940 MHz and memory clock from 1375 MHz to 1400 MHz.
Both boostings are not aggressive but enough for a stable FSX performance. I may further use ASUS’s SmartDoctor to finetune the card’s GPU clock in the future. But I certainly won’t install the company’s GamerOSD as it causes serious stutters in FSX.