The AnTuTu site has since been revised and the benchmark score for the Intel Atom Z2580 is now 20% off with the RAM score itself cut in half. Scores for other processors remained the same. The 20% cut in the Z2580's score now puts the Samsung Exynos 5 Octa on top of the Intel silicon based on benchmarking the Exynos 5 Octa powered Samsung Galaxy S4 against the Intel Atom Z2580 flavored Lenovo K900.
Things could get wild next month when a major revision is scheduled for the AnTuTu testing standards.
Intel Atom Z2580 retested on AnTuTu after revision to the site
source: EETimes via SlashGear