Which one of these is the better buy?

Considering the price, I'd recommend the the 755M SLI because of the price and it's increased performance versus the 750M SLI. From what I can see, they're both SSHD so they're hybrid drives (not actual SSD's). They're considered an in-between of HDD and SSD's (more durable and faster than an HDD, but slower than an SSD).

However, the issue with SLI GPU's is heating. I would recommend Lenovo's new Y50 option (just the base model) with the 860M. It only costs $1,049.99 and the GPU is a much faster and safer option.

The 860M performs faster than the 755M SLI (http://www.notebookcheck.net/NVIDIA-GeForce-GTX-860M.107794.0.html) and it produces less heat with more power efficiency. It's an overall better GPU than the older 755M SLI with the same price. You're only missing out on the 8GB SSHD, but the storage capacity of this is so small you can't even put an OS onto it (OS takes up about 16GB's).

Here's the Y50 - (http://shop.lenovo.com/us/en/laptops/lenovo/y-series/y50/).

Let me know if you have any questions! :)
 

orlbuckeye

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I agree with Jason about the SLI graphics in a 15.6" laptop with a smaller case. You want a case with lots of air vents for SLI graphics and there are some 17" and 18" laptops with huge air vents to keep temperatures lower.