Multiple GPUs Help

[wrigglingears]

I'm going to be getting new graphics cards for a desktop gaming/general workstation/hash cracker by night, So I'd like to get something that is able to reasonably perform in all these areas. I'm currently eyeing either 2x GTX970 or a single GTX980Ti for my build, the budget for graphics is about US$600-700.

It seems to me from online benchmarks that for the gaming side, 2x 970s will perform similarly to a 980ti, so that part is alright.

Based on benchmarks that I've seen around the forums, it seems that a single 970 performs at about 75% of the 980ti, in terms of hash speed.

Since 2x970 is approximately the same price as a 980ti, would the 2x970 be the better option then? I also understand that the TDP of the 2x970 is only 30W more than the 980ti, so it seems pretty comparable.

Also, on a side note, would cudahashcat be able to use both gpus if SLI was turned on? Or would I have to keep switching between SLI on/off whenever I wanted to switch from gaming to cracking...

[epixoip]

2x 970 would show the best performance. But yes, you would need to switch off SLI before using hashcat.

[wrigglingears]

I've just been looking around the local second-hand sales forums, and I've found a few used 7970s at around US$140-150 each, would it now make more sense for me to get 4x7970 instead for the same total of around $600, since each one has a better hash/$ than the 970?

I'm a little worried about the amount of heat the 4 gpus will put out though, and whether anyone has experience trying to cool 4 of these cards in the same case...so far I'm only able to source for 2 blower-style ones, the rest will have to end up being oem designs.

[azren]

You will have issues with heat using oem 7970. Only go with reference design card! My advice better to go with 970 instead.

Best regards,
Azren

[wrigglingears]

How about if I was able to watercool the other two cards that aren't reference? That would mean that the heat is being dissipated outside of the case?

I have seen a few times people mentioning not to use watercooling but I haven't been able to figure out why it would be worse than oem designs.

If I were to get the 970s instead I would still need to source for reference designs right? Those designs aren't as easily available here as opposed to the oem ones...

[azren]

970 reference design card is a unicorn https://hashcat.net/forum/thread-4532.ht...ht=unicorn


epixoip suggested the following instead:

ASUS TURBO-GTX970-OC-4GD5
MSI GTX 970 4GD5 OC

And as for watercool in my humble opinion will be complicated.

Best regards,
Azren

[wrigglingears]

thanks for the help (: