1. You're comparing single hash speeds to multi-hash speeds, and dict + rules to brute force, etc. These are not an apples v oranges comparisons.
2. My benchmarks are at +250Mhz. You said you're running at stock clocks.
There's absolutely no reason not to overclock Maxwell cards, they are clocked very low and have tons of overclocking headroom. Should be able to run up to ~1515 Mhz without overvolting. You will also need to do further tuning to set PowerMizer mode, performance level, etc to ensure the most consistent performance.
2. My benchmarks are at +250Mhz. You said you're running at stock clocks.
There's absolutely no reason not to overclock Maxwell cards, they are clocked very low and have tons of overclocking headroom. Should be able to run up to ~1515 Mhz without overvolting. You will also need to do further tuning to set PowerMizer mode, performance level, etc to ensure the most consistent performance.