Presjar

I use 2x120GB Intel 520 Drives in Raid0. I am still running on a z68 platform that doesn't normally support TRIM commands. However, a guy hacked in the Support into my motherboard BIOS and now it works great. I can prove the trim function works by opening an image file in HEX editor and finding a string of characters. You then open your SSD in Hex and search for the hex string and look what the location in bits is. Delete the image file. Wait a bit. Browse the SSD in hex again back to the original file location. All the bits in that area will be 00.

I would go with what your budget allows. If the NAS maker says the drive is compatible in the documentation then it should be ok. However, the WD Red drives are good value. Especially because you get a good warranty.

You are still going have issues getting good frame rates at 4K. Unless you can get SLI 970/980. Even then, you can get some poor minimum frame rates

Blower fans would work better in SLI only if you have a space between them. Obviously when they almost are touching on a standard setup there is no way for the upper card to suck in cool airflow.

ACX card looks like this

Standard ACX cooler works really well for SLI if you have an extra slot gap between the cards and a good fan to move the exhaust air out. I have been impressed with it so far!