That setting should give around 0,22-0,23Khs. core clock is +155 and memory clock is +475 in msi afterburner.
That's too low. You can get 1200 H/s from your card -> http://www.whattomine.com/
Default(start) values are adapted for 1000 kh/s of Scrypt(280x). (copyed from whattomine)
A 750ti does roughly 260Khs scrypt can be bumped to about 330Khs with oc and the bios mod for more power. 1,2Khs was maybe true when nf was 15 but not at nf 16. If you know a config for a 750ti that does 1,2Khs at nf 16 then by all means please post it.
1000 H/s for a 280x and 1200 H/s for a 750ti, those are the default values for Chacha Nf16. Are you saying that both are too high?
It calculates it after the scrypt hash rate, the default rate they put in is 1000Khs. Try changing the scrypt hash rate and see what happens in the chacha hash rate tab. My r9 280x runs 760Khs in scrypt mode but only 255Hs when mining YAC, my 750ti run 336Khs in scrypt mode and 240Hs mining YAC, both speeds are at current N factor 16. Basicaly its just gives you a rough estimate of hash rate for the diffrent algo when you put in the scrypt hash rate.
I know, I am the owner
The current (wrong) multiplier for yac was 0.001, which would put 280x at 730hash/s. I distinctly remember someone giving me those number when yac went nf16. Well hard lesson for the next time to always confirm by yourself. 
Its an older but still decent system I installed them in with 4GB DDR2 ram and a Q6600@3GHz running windows8.1. 
