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?