There are a few main points to look at, and lets start right away with the main difference first:
-The 980m is much more powerful than the 970m. The 970m will pull 72FPS average in BioShock Infinite but the 980m will put 91FPS, and Crysis 3 gets 33 vs 43FPS respectively. The Video Memory on the 980m also has an extra gig of ram giving you a total of 4GB with the 970m has 3GB. These difference can really make the difference between high and ultra on todays newest games.
-The next is the CPU. The 752 has the Skylake chip. This is a less power hungry CPU so it will slightly extend your battery life. Its also about 20% faster than the chip in the 751. For gaming this means you will pull about 4-5 more FPS. Its not a huge difference.
-DDR3 vs DDR4. The 752 offers DDR4 made possible with that new skylake chip. This ram is much faster than DDR3. This can produce slightly lower loading times and will push the overall speed of the laptop by small percent.
-The 752 Offers a Thunderbolt 3 port. This is only good if you intent to use Thunderbolt 3 devices, or anything USB-C. Thunderbolt 3 is extremely fast, but the devices that use it are extremely expensive.
-They are now offering RGB back lit keyboard keys. This can look really cool for customizing your keyboard.
-3D Vapor Cooled CPU & GPU. This is new technology used in the latest Graphics cards, designed to help keep your chips as cool as possible. This can be beneficial for overclocking.
These are the main differences. The main thing to consider here that GPU. Yes the newer laptop has faster RAM and a faster CPU. However, since its using the 970m, it will still be slower than the 751 for games. Also, you can buy the G751JY for $1,499 right now that has the 980m, but the 752 with 970m costs about $250 more. Even if you decide to wait for the 752 with 980m in December it going for $2,500. That's a thousand more dollars for a minimal performance increase. Don't get me wrong, it looks amazing. But $1,000 is way to much for such a small performance increase.
