Just to get a better idea, Apple made the jump to the ARM Cortex A8 with the iPhone 3GS back in 2009, which is a whole generation ahead of the ARM11. As for NVIDIA, they have the Cortex A9 in the Tegra 2, making it a couple of generations ahead of the ARM11.
Strangely enough, it isn’t to say Nokia has no experience at all with the Cortex A8 in the past, since the N900 does boast of that chip. Apart from that, the Nokia 500 lacks a graphics processor, so even if there was a clock speed increase compared to other Symbian^3 powered devices such as the N8, E7 and C7, would mean those additional clock speed is spent rendering everything in software.