Question: my 900 is nice and fast, and from what I understand WP8 runs nice and light on even modest hardware such as the Lumia 520. What's the real benefit of a quad-core Snapdragon 800 in this case? Especially given the WP8 tombstones apps rather than run them in a true multitasking fashion (done for battery life and overall efficiency, no?)...
Just curious. I'm pretty excited about the 1520, but aside from having to push more pixels, I'm not sure what all the extra power is for.
Think of it more of a future proof than "what do I need for it", especially as 800 battery life is reported to be same or even better than Snapdragon 600. When the next device comes up with even more power, you will be in a very good position with Lumia 1520 as you truly have device that had the most powerful SoC available in that gen. New games or heavy apps should be a no-brainer to run on your Lumia 1520 in 2 years time, but that might be different case for Lumia 720. Hell, even Nokia Pro camera on Lumia 1020 with its 2GB of RAM is not lag free. it will be without doubt on Lumia 1520.
We need to remember these are not CPU's and not only related to power, the real term here is SoC. it's the heart of the whole device that determines much of it connections for example.
There are many things Snapdragon 800 brings, example new GPS chip that is featured on the new iPhone 5S and on Qualcomm 800 devices, support for 4k video capture and decoding, USB3.0 support, 802.11ac natively supported, Quick Charge 2.0 feature that lets the device charge faster, DSP that can switch the phone in to ulta-low power levels for predefined software (music playback or such. Needs to be enabled by MS or Nokia on that specific app) and more possibilities in general for hardware manufacturers to bring new tricks. I got a feeling we will see some with that 20MP camera sensor on Lumia 1520 that Nokia was not able to do on Lumia 1020 quite oldish SoC.