MBP extremely slow after SSD installation

[Sweps]

Hi guys,
I've just installed a new kingston v300 120GB SSD on my MBP 2012.
The Mac was insane slow already during the OS installation, I tried to install El Capitan, but it took too much time and it kept freezing at 80%.
So I decided to install Maverick, and it went quite good despite the fact that it was still too much slow.
I hoped it would have been better after the installation was complete, but instead now it's pretty unworkable. It took ages to do whatever action.
I have a SATA 3 interface, and 4 GB RAM.
Thanks!

 

[Hellhammer]

Run a disk benchmark to see if there's something wrong with the drive's performance.

https://itunes.apple.com/us/app/blackmagic-disk-speed-test/id425264550?mt=12

 

[JTToft]

Kingston V300 is not a fast SSD, but you shouldn't be seeing what you're describing.
It's feasible you have a bad SATA cable. You might try taking the SSD out and connecting it externally to see how that works.

 

[robeddie]

Probably something got damaged in the install? That said, should have gotten an 850 evo. I've got 2 1tb evos in my 2012 MBP and they're super fast and going strong 13 months in.