$1800 build?
So we're building a dedicated password cracking machine. 

We have put $1800-2000 aside and the machine is only gonna be used for password cracking. 
Now it's been a long time since I last looked into password cracking, but I remember back then, Radeon was king. 
Is it still king or has Nvidia finally caught up? 

We need to buy everything, since we have no spare parts laying around. 
It will be put in the basement, so noise isn't really an issue. 

If somebody could help us putting a setup together using http://pcpartpicker.com we would be very greatful Smile
$2k is still low budget for a cracking rig.
For best performance for the buck you still have to consider buying 290x. You may be able to snap some decent bargains on ebay but you still have to calculate around 250-300$ for one gpu.
The biggest problem for your budget is probably the fact that costs go up exponentially the more gpus you put on one board (second powersupply, case, cooling).
For $2k if you are lucky you can go for 4x290x that leaves you with around $800 for board, cpu, ram, case and powersupply. A 1500W powersupply is costly but neccessary and shouldn't be cheaped out on. There are some discussion on which boards to use, choose one on which you can put all gpus without the use of extender since you may need another $100 just for the extender and another 100-200$ for the casing to arrange the gpus. Also watch out which CPU you choose since there may be a difference in the pcie lanes they can address, i7 >4770k is a good choice.
In the worst case a 290x can draw 400W each. A 1500W PSU ain't gonna cut it. Don't buy AMD.
Thank you for the input.

We talked about it and since our budget is pretty locked (and the prices that we pay in this country), we decided to stick with 2xR9 290x. Sadly they only seem to sell reference cards, so we're kinda stuck with that. Would they do OK?
Also, for the price of 1 GTX 980 I can get 2 of those R9 290x - which is why I decided to stick with R9 290x too.


How does it look? :-)
A 970 archives about the same rate as a 290x according to these benchmarks:

To be fair, the 290x was done with a much older version. Still, speed differences should not be significantly different.

You might consider sticking to 970s.

btw, by "reference cards" you mean OEM cards it seems. Reference cards is what you should get if possible. But with only 2-3 cards you're unlikely to run into major heat issues even with OEM coolers.
Looks pretty good, if we can save almost 50% of the power.

We ended up with two of these: https://www.asus.com/Graphics-Cards/STRI...DC2OC4GD5/