DraStic

I'm going to either update this post or post more as I test more games due to not getting much time to mess around with it.

Phone is a rooted LG Volt (Snapdragon 400 (32 bit), 1.2 GHz quad core, Adreno 320 graphics, 1 GB RAM, Android 4.4.2 (LG G2 skin)) with Root Booster(Speed mode) running (I don't know if it's affecting performance any). I've only tested Dragon Quest IX: Sentinels of the Starry Skies so far, and there wasn't much of a difference in speed between 3 and 4 threads. Got between 87-100% speed (hovered around the 90%s, and dropped down to 40% whenever I change areas), though it is worth noting that the first time I set threads to 4, performance died (90% at the absolute highest, hovered around 70-80%), though a reset fixed it. Settings are-
Frameskip: None
Filter: Scale2x
High-Resolution 3D Rendering
16-Bit Rendering
Disable Edge-Marking
Multi-Threaded 3D Rendering
High audio latency

Let me know if changing any of these will improve performance any (minus frameskip options), so I can adjust accordingly. Like I said earlier, I plan to mess around with it more, low RAM makes using games on my phone a pain when I'm using other apps on it though.

Does 16-bit rendering make any difference in performance for you?

On my Moto G 1st gen, I got about 5% performance boost from using 4 thread vs 3. I tested the intros to Phantom Hourglass and Spirit Tracks, and the fire boss intro in Spirit Tracks, and they took 42/44, 51/52, and 55/59 second to complete, respectively, with 4/3 threads. All had no filter, high resolution rendering, and zero frameskip. The two game intros I tested with fast forward enabled, set to unlimited. For the fire boss, fast forward was disabled.