You'll notice that even the best CPU choice on the G505 is only half the benchmark score of the Lowest i5 choice on the IdeaPad Z580. Don't choose an i3 for any kind of high end gaming. You really want an i7.
Next, you'll note the video card benchmarks.
G505 has AMD Radeon™ HD8570M 1GB -- 916 score
IdeaPad Z580 has Intel HD 4000 graphics -- 456 score
G505 - Weak processor, decent video card - Multimedia Laptop
z580 - Good Processor, pathetic video card - Business laptop
Neither Machine is marketed nor built for gaming. You won't run BF4 well on either one.
You should look at desktop PC's for performance gaming, or pay a premium ($1,500+) for a Gaming Laptop Try one of these