The rate is likely falling because the GPU is throttling itself. The 295X has a very low Powertune target temperature -- it has a hard-coded maximum value of only 75C (compared to the 290X, which has a max target temp of 95C). In your screenshot, both of your GPUs are practically already at 70C, so you're extremely close to the maximum temperature that card can handle. This is why we have never recommended the 295X for hash cracking.
For your second question, read the wiki article on rules and check out the -j flag.
01-18-2015, 10:09 PM (This post was last modified: 01-18-2015, 10:20 PM by epixoip.)
Powertune doesn't just throttle for heat, it also throttles for power consumption (hence its name.) You are aggressively overclocking, so you are surely exceeding the amount of power the card is willing to draw. You have to do some tuning to try to convince it not to throttle, but even then it's a losing battle. Your card is not designed for compute, and is known to be problematic with oclHashcat.
There's absolutely no way your card is only drawing 265W @ 1100 Mhz under load. The 290X doesn't even draw less than 300W at 1050 Mhz. So GPU-Z is absolutely not to be trusted with those measurements. The 295X is a 500W+ card, pure and simple. Your card is not designed for overclocking, and absolutely is not designed for compute, so you're certainly pushing the power limits of that GPU. That's certainly why you are seeing the GPU throttle.
01-18-2015, 10:25 PM (This post was last modified: 01-18-2015, 10:34 PM by epixoip.)
I most certainly am not envious of you. Nor am I envious of your inability to read these forums where we have repeatedly advised users not to buy the 295X. It might be good a good card for pushing pixels, but it is not a good card for oclHashcat.
01-18-2015, 10:43 PM (This post was last modified: 01-18-2015, 10:47 PM by epixoip.)
No, it absolutely is not the best card to buy for oclHashcat. You are sorely mistaken. 2x 290X are cheaper, faster, and behave much more civilly. GTX 980 however is the all-around best card to buy.
The problem is not the with the program. The problem is with the card. The 295X is designed for gaming workloads, and absolutely not designed for compute workloads. As NBZ told you, if you know what you are doing, you can make the card behave a bit better through Powertune tuning & some hardware hacking. But it still won't be ideal.