3 cards giving you about 3,600 khash/s?
I have 4 cards giving me about 9,500 khash/s for X11 so your numbers look a little low to me.
I am running the very latest ccminer from djm34 compiled with CUDA 6.0
(
https://github.com/djm34/ccminer)
is this value is normal for gtx 750 ti for x11 mining fractal
[2014-07-16 17:22:38] Stratum detected new block
[2014-07-16 17:22:38] thread 0: 23003137 hashes, 1193 khash/s
[2014-07-16 17:22:38] thread 2: 25624577 hashes, 1220 khash/s
[2014-07-16 17:22:38] thread 1: 26542081 hashes, 1261 khash/s
[2014-07-16 17:22:44] thread 2: 7303333 hashes, 1189 khash/s
[2014-07-16 17:22:44] accepted: 374/374 (100.00%), 3643 khash/s (yay!!!)
[2014-07-16 17:23:01] thread 0: 27686087 hashes, 1200 khash/s
[2014-07-16 17:23:01] accepted: 375/375 (100.00%), 3650 khash/s (yay!!!)
[2014-07-16 17:23:17] thread 2: 40878269 hashes, 1223 khash/s
[
2 x 750 (non ti) give me 4.1-4.2 on X11. Overclocked (see my other post).
planning to replace my 40 280x with 66 Ti's , will save 1/2 of power costs.