Nokia may already have a quad-core Lumia phone in the works as suggested by GFXBench results, the GPU mentioned in the benchmark results is Adreno 305 which is a part of the new mid-range quad-core Qualcomm 400 chipset. This chipset supports both Android and WP8, providing fuel to the rumor. Furthermore, Microsoft has already been working on a GDR3 update for Windows Phone 8, which is supposed to bring support for quad-core processors and 1080p displays. Therefore, it is not entirely out of the realm of possibility that, Nokia, one of Microsoft's primary WP8 partners is already tinkering with a build of WP8 with GDR3 update.
The benchmark also recorded that the display of the device had a 720p resolution, now if we go on a different path, the Noka EOS too has been rumored to have a quad-core processor. So now we can either have the Nokia EOS posing in the GFXBench scores with a quad-core processor, or a new Nokia Lumia device altogether. Till then, lets hope WP8 catches up atleast in terms of the number of cores, if not in usability.