Slow hashing with R9 290

[kltye]

1. you mentioned the mask ?d?d?d?d?d?d?d?d?d?d but the status screen of oclHashcat clearly and undoubtedly shows us that you are lying about it. What I mean is, that it should be very clear to all of us that ?d?d?d?d?d?d?d?d?d?d is different from 84?d?d?d?d?d?d?d?d :

Code:

Input.Mode.....: Mask (84?d?d?d?d?d?d?d?d) [10]

The problem here is that, as mentioned in dozens if not in hundreds of other forum threads mentioning exactly the same "problem", the left-hand side is very small. Since the beginning of your mask, i.e. "84...", is static, oclHashcat cannot reach full accereration (in general. This of course is particularly noticeable with so-called fast hashes). oclHashcat will always update/change the left side most frequently, and because it is hard-coded/fixed, it won't vary a lot. As said, the problem is that oclHashcat can't reach full accereration if the mask (or left-hand side of the mask) is constant (or part of it).
The before mentioned forum threads that deal with exactly that problem also mention several workarounds and tricks (which I won't repeat here, use the search function). In some cases, even using a pipe makes sense and could be faster (this is especially true if the hashing algorithm is a so-called slow hash, as is -m 2500 = WPA/WPA2)
Also note: there is sometimes a tradeoff between "the smallest mask as possible" (with the minimum of keyspace) and "the mask with best acceleration". This depends from case to case. For instance, having a "smaller mask" (less keyspace or hard-coded left hand side) could result in less speed (particular noticable with fast hashes) but at the very end it could still be faster compared to a run with a much larger mask (where the keyspace is larger).

2. R9 290 is not the same as R9 290x

3. there is a special benchmark mode which you can use to test the speed of your GPU(s), e.g. -m 2500 --benchmark

4. you forgot to specify a workload profile, i.e. -w 3 for "full speed". It doesn't make much sense to speak about "Slow hashing" without even specifying the -w 3 command line option

Thanks for your detailed explanation; it looks like -w 3 was the switch I had missed. It performs exactly the same (at least to my untrained eye) no matter which mask I use. I'm not looking to eke out every single bit of performance from my GPU - I was just wondering why there's such a huge difference between the numbers I was seeing vs. what I was expecting. Thanks again!