If your pool doesn't give you a network diff of 1.93T, either you're not mining bitcoins or your pool is lying to you.
That screenshot looks about like it's supposed to. I'm going to guess it's a "your hardware sucks" situation. What happens if you run at lower speeds? What hashrates are reported at 50, 75 and 100MHz?
I did a test where I started it at 100 MHz and seemed to lose one third of the output. I presume that means that I got to contact the original seller and make a warranty claim?
Is the device getting really really hot? What is the ambient temp?