A Radeon HD 6990 for hash cracking. Good or bad idea?
Hey guys,

I've got a mate selling his old Radeon HD 6990 for like $150 US which is pretty cheap as far as I know. What are the downsides of cracking on one of these monsterous beasts and would you recommend a different card?
If you can get a 6990 for that price you should probably take it. Only downside is its power consumption.
Yeah, power and heat are definitely a challenge with the 6990. It's a 425W card with a TDP of 375W. You may have to do a little underclocking to make it happy, or start seeking exotic cooling solutions. Minga went so far as to submerse his in mineral oil.
150 is a nice price , i love those 6990... have 4 on water and they kickass.
It's an okay price. They're selling around $130 on eBay right now.

I personally think they're far more hassle than they're worth. We ended up with 24 of them, then promptly sold them all and replaced them with 7970s.
Just measured it out and my case is just slightly too small for it anyway unless I do some DIY cutting or take the side of the case off. I've heard they're quite loud too, power isn't really an issue as I've got power included in the cost of my place here. I suppose cooling would be another issue which I'd have to deal with. Another card that I may have the opportunity to buy is an old 5970 that has hardly been used for $50 US.
Power is always an issue. The more power a card draws, the harder it is to cool.

5970 is the same length as the 6990. They are both dual-GPU cards.
I've also been offered a 6950 for about the same as the 5970 although it's nowhere near as powerful as the other cards. I'll have to take a look into the cost of a new case if I opt for the larger cards and extra cooling. Currently I'm sitting on just a stock standard 7750, so it's a bit of a change. I ended up getting an 800W power supply when I put my PC together though for some silly reason.

The only real reason why I was opting for those cards is the fact that they're cheap. However, after all the cooling and modifications I'd have to make to my PC, I'm not sure that it would be very cheap.
There's no real market for used GPUs now that GPU mining is dead, so used GPU prices are incredibly reasonable right now. Have a look at what's on the market, I think you'll be surprised. 7970s are selling for around $100-130 right now. Hell, one even sold for just 99 cents on eBay a couple days ago.
once you go 6990 , you wont go back.

btw 280x are very good in price:power relation