I'm building a new rig but I'm using an old Samsung 850 Evo 256. Originally I was going to get a Western Digital black for my media, games and everything else but after thinking about it with the noise, heat and lack of reliability with a mechanical hard drive, I decided to get a second SSD for storage. I usually only play 1 or 2 games at a time and my htpc has most of the movies and everything else that I watch anyway so I don't need that much space. The price on the 512 and one terabyte ssds just sucked. So I ended up getting another Samsung 850 Evo 256 but I got the pro model mostly because of the warranty being a full ten years for peace of mind.
I may do a tiny bit of video and photo and maybe even audio editing and that's the kind of stuff that I don't want to ever lose even though I will be making a backup.

So should I put the operating system on my old solid state or should I put it on the new Pro? The older one is a little over a year old but it really doesn't have that much use on it.

Also using ssds only and two of them; is there anything I need to do aside from turning off Windows defrag for a better experience? Thanks in advance

Yeah that makes sense. My old 850 was bought in March 2015 so I guess it's not THAT old. That's cool because now I can just load everything on the old one and get it up and running while I'm waiting for the new one to ship. Thank you, I just wanted a little bit of reassurance I guess

I'm curious as to what motherboard you are using

You probably wont see any difference in speed as most ssd drives will max out sata 3 anyway. For lifespan its really going to depend how much they are rated for in writes, you should be able to find that info in the specs some were. What OS are you using? If its windows 10 use GPT and dont worry about the defrag, windows should know you are using ssd and us the trim command instead, do not turn that off.

Put the OS on the Pro drive, it's faster. Assuming you actually got an 850 Pro not another evo, your post is kind of confusing in that regard.

agent8
Yes, The old one is the Evo and the one on its way is a pro. My research shows almost no noticable increase going with the pro in real world usage. I went ahead and loaded the old one with 7 tonight.

+1.   I have an 840 Pro and an 840 standard.  When benching them, the difference in numbers is there, but marginally.  I've run the OS on both drives at one time or another and couldn't tell the difference in day to day activities or gaming, etc...