Nice example of what artifacts look like in FurMark when overcloking settings are too high!
The graphics card was the Gainward HD 4870 Gold Sample:
From the Gainward HD 4870 GS’s datasheet, this card has two modes: normal mode and turbo mode for two different overclocking speeds:
Dual BIOS support for easily select two different
over-clocking speeds, Normal mode and Turbo mode.
750MHz core clock, DDR5 950 (DDR 3800) MHz memory clock (Normal Mode).
775MHz core clock, DDR5 1000 (DDR 4000) MHz memory clock (Turbo Mode).
The owner of this graphics card didn’t know it, but the turbo mode was enabled. And with a power virus like FurMark, artifacts can quickly appear!