Overclocking the iGPU in A10-6800K

Hello Everyone. I am currently overclocking my computer for a school project (my senior project is building and overclocking a computer).

I currently am focusing on overclocking the iGPU but can only get up to 1013MHz with my Zalman LQ315. Thats less than 100MHz difference than when I overclocked the iGPU with the stock heatsink. My temps are only 40 C when I run FurMark or OCCT's GPU stress test, but when I go to 1094MHz, OCCT freezes up and a balloon comes up saying "the driver has stopped working, but has recovered" (or something along those lines). I tried increasing the the APU1.2V to get better stability, but I went up to 1.25V and that didn't help stability at all.

It might just be me, but it seems to me that I should be getting a lot higher OC on the iGPU. I was able to OC my CPU  by 11% more with the LQ315 than with the stock heatsink. Currently, I'm only getting a 6% increase with my iGPU. Is there anything I'm missing or not understanding to get a higher OC?

Here are the specs of the computer:

Motherboard: FM2A85-M PRO

RAM: GSkill Sniper Series 2400MHz 2x4GB

PSU: Rosewill HIVE 750W Modular

Cooler: Zalman LQ315

Case: Corsair 200R

Here are the settings I currently have stable when focusing solely on the iGPU:

APU frequency: 105MHz

CPU multi: 39.0

Vcore: 1.275

Thanks for anyhelp you can give me!

PS. Yes, I know that my PSU is way overpowered for the system and the LQ315 is like putting a turbo on a Fiat 500.

 

Oh, I forgot to mention my RAM settings.

Frequency: 2239MHz

Timings: 10-12-12-30