All phones have a graphics chip, that doesn't mean it's a GOOD graphics chip. It also very much doesn't mean that it's fast enough for the screen resolution.
In the case of your Photon it was also running Gingerbread which didn't have 2D hardware acceleration. Made especially worse by the fact that Tegra 2 doesn't have NEON, so the software painting was extra slow on that device AND it had a "high" resolution.
It was a badly designed device from top to bottom. A quad core wouldn't have done a damn thing to help its pitiful performance (especially as there's still only a single UI thread doing the painting)
No it was not running Gingerbread, the first thing I did was hack it. It was running Cyanogen based on Ice Cream Sandwich.
I would not be surprised by the fact that it was poorly designed, and it's the main reason I will did not nor will not consider another Motorola phone in the future.
GPU performance and memory bandwidth are waaaaaaay more important than an extra 2 cores that'll be turned off 99% of the time anyway.