The site got its news from German tech site Planet 3D Now!, which published some screenshots and benchmarks as proof.
However, unlike with the story of the unlocking of the fourth core, the German site has no idea how they did it. They were overclocking and playing with the BIOS when suddenly the disabled 2MB L3 cache came alive. It was definitely not a wrong readout, because the benchmarks show the performance was indeed higher when the extra cache was enabled. They speculate it may be a BIOS bug that enabled the cache, because after doing a CMOS clear the chip could once again access only 4MB of the L3 cache memory.