Why is DayZ running worse on my new hard drive than on my old one?

So the stock harddrive on my Lenovo G505s laptop recently crapped out, so I bought an average priced SSHD (I was tight on money, couldn't get SSD) and clean installed Windows 7 OEM (the laptop previously had Windows 8). I didn't transfer, just installed all of my old games, including DayZ.

Now on my old HDD, I was able to run DayZ comfortably on average settings (messing with config settings, I got about 40 fps in cities, 60 outside). I figured with this new SSHD, plus having W7, would let me run it at least a tiny bit better, it gave me a boost for my other games. But for DayZ it make it much worse.

Now I have to reduce the resolution, make the config settings for view distance lower, set EVERYTHING to low in-game… And that get's me about ~25fps in cities, 30-40 outside! Now I can live with the fps drop to a degree, but now my game looks terrible.

Just wondering what the hell happened. I know DayZ has terrible compatibility issues. Does it have to do with the SSHD? Windows 7? I can't imagine it running better on W8 that W7.

All drivers are updated properly, also.
Added (1). I mean, if anything, it should run exactly the same as when it was on my old HDD. And btw, the new SSHD is a Seagate 1TB (ST1000LM014). Everything about is better than the stock harddrive.

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