Linux Devices' guess is....

"Archos calls the new devices the world's first Cortex-based products. Although processor specs are not listed, the PMPs are likely based on the Texas Instruments OMAP35xx line of system-on-chips (SoCs), which are in turn built around ARM's powerful Cortex-A8 core. Considering the video focus, the devices probably use one of the two high-end OMAP35xx models that offer video acceleration: the OMAP3530, which also includes an OpenGL ES 2.0 accelerator, or the OMAP3525, which does not. Both SoCs are clocked at 600MHz and started shipping in late July."