Aspire E1-451G VGA Driver 8750m and 7640G issue

I've had the same issue and discovered that computer makers develop their own custom software/drivers for laptops in amd dual graphics configurations. Both amd and Acer will tell you to use graphics drivers from the pc manufactured(Acer). So the drivers you get here were made for your specific model. I have had limited success using drivers from amd. If you do try some of the drivers from amd I would look for the vision engine control center, It's designed for amd dual graphics setups in laptops.

If you do decide to try different drivers make sure you test them properly, I'd hate for you to ruin you computer. I use a combination of msi afterburner, amd system monitor, cpu z, furmark, and heaven dx11.  Make sure your computer idles at its minimum clock speed, and does not idle warmer then with your stock driver. If it idles ok then do some gaming while recording with system monitor. Note you should do all these tests with your stock driver so you have a baseline to compare with. If the gaming goes well try heaven dx11 and see if your score improves over stock, or at least stays consistent.

I should mention that after all the pain I went through myself, I eventually gave up and went back to stock. Just like the manufacturer suggested in the first place, lol.

Good luck

Edit: Just want to add one important thing before you start messing around. Create a restore point in windows! I personally would also create a disk image and save it to another computer on your network or to an external drive. Also an easy way to monitor temperatures is to touch your computer, lol, and listen to the fans. Probably the first thing you'll notice after installing a driver that is not working is that while idling your fans are going nuts and your computer feels warm. At that point restore from restore point immediately.