Which of these two Lenovo's is better for schoolwork(Powerpoint, etc.), engineering programs such as AutoCAD, downloading movies, and for gaming. I am not a hardcore gamer, but I want okay gameplay for when I do play. I usually only play Black Ops 2 and lower games, so I would like decent gameplay for that.
Neither is particularly good. The Lenovo G710 is better for AutoCAD because of the higher resolution I suppose. The higher the resolution, the more you can see on the screen at any one time. It has the Intel HD 4600 graphics core. It is slower than the Radeon HD 8650g in the A10-5750m, but considering that Intel hasn't really bothered with focusing on games until three years ago, the Intel HD 4600 is decently impressive.
The G505s is more gaming oriented of the two. The Radeon HD 8650g was the most powerful integrated graphics core before AMD released their Kaveri generation APUs this year. I would say it is about 33% more powerful than the Intel HD 4600. With a resolution of only 1366x768 I don't think it is really suitable for AutoCAD since lower resolution means you will see less on the screen at any single time. I would think AutoCAD and 1366x768 resolution would get tiresome very quickly. I don't use AutoCAD so I don't know how much it relies on the CPU and the GPU cores.
The A10-5750m is a quad core CPU while the i5 is a dual core CPU. For applications that only use 2 cores, they will perform better with the Core i5 CPU. For programs that can use 4 cores, they might perform just as well or better on the A10-5750m vs. the Core i5.
For schoolwork in general, I would prefer higher resolution compared to lower resolution. Especially if you are going to have two documents open side by side for referencing.