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I sold my GTX-580 and returned the HD 6770 (didn't quite perform as I'd hoped). So now I need at least one new GPU (I can run two on my mobo). The way I see it, I have to have a high-end GPU and it's been time to upgrade for a little while. So I'm not really considering this an "investment" in mining, but buying an already necessary/useful item that I can mine with. I've got 2x PCIEx16 slots, so I wanna put the baddest hashing machine possible in them. Don't really care about the cost, as long as its not wasteful in terms of hash-rate/$ or hash/W.

According to Bitclockers, the HD 5970 achieves a hash-rate of 700MH/s! That sounds great to me... The idea of running two of these cards and hitting 1400MH/s in mining is definitely an appealing prospect, and those cards should be great for gaming and graphics development at the same time. But I had a few questions...

For starters, is anyone here running a 5970 or two? What sort of actual hash-rate are you getting out of it? And is that right out of the box or after over-clocking? And how about power consumption and heat?

Also, does anyone have a used 5970 or two they want to sell (for BTC or USD)? I know I can get one on Amazon or eBay, but I'd definitely like this economic activity to fall under Bitcoin!  :D

Regards,

--ATC--

https://bitcointalk.org/index.php?topic=129118.0

7970 all the way. Plays games awesomely fast. It can also hit 700MH/s, but can also be a lot more efficient than a 5970. It's also not 2 years old like the 5970, so you can get one with plenty of time left on the warranty.

Interesting coincidence that you'd suggest the 7970 -- I'm also interested in those, and someone here just told me they have one for sale!  :D

Crunched some numbers on the mining calculator and it does indeed sound like a winner.

crazyates (or anyone else) do you think a 6870 Sapphire is worth running? Local PC store offered to sell me one $40 below retail price.

It seems to me I can get that 6870, giving me around 300MH/s, and then get a 7970... the two of those will give my PC close to 1GH/s, if I'm not mistaken.

I would pass on the 6870.

Explain

Your best bet is two 7950's. They overclock really high and will match a 7970. Total hash rate should be around 1.4 g/h with bitcoin mining.

Cost = $290 each.

Yeah I would probably go 7950

6870 is 850 MHz with 1120 shaders. 7970 is 925 MHz with 2048 shaders.
850*1120/925/2048 ~= 0.5025

A 6870's performance is about half of a 7970 as far as mining is concerned, and is probably less than half as fast for gaming (architecture improvements and whatnot) compared to 7970.

2x5970 gets 1305 MH/s used costs $150 a piece. Combined power is 450W with down clocked ram.

You're forgetting that the 7970 uses the GCN architecture, which is very different than the 6870's VLIW-5. It's not exactly an apples-to-apples comparison, so it's not going to be exactly 0.5025.


I don't think so. A 7970 is already hard pressed to get to 700MH/s, so downgrading to a 7950 (with its fewer cores and lower speeds) makes it almost impossible to hit 700MH/s per card. Can you show me where a 7950 was able to OC high enough?

I know its GCN. Still, the hashrate per mhz per shader is pretty damn close to a VLIW5

My mistake . . what I meant to say is, an OC'd 7950 will match a stock 7970 easily. Maybe not 1.4 g/h, but 1.2 g/h easy.

For craps sake dont get a sapphire. Their warranty and rma process sucks horribly. I know thus for a fact. Send you back shit too.

I have seen 7950's overclocked to a level that provided around the same FPS in games that a stock 7970 could get.  However, mining is a whole different thing.  The 7950 has fewer stream processors, making it a slower miner than the 7970 by around 100 Mh/s.  Is 100 Mh/s worth $100 though? Probably not.

$275 (http://www.newegg.com/Product/Product.aspx?Item=N82E16814131478) vs $360 (http://www.newegg.com/Product/Product.aspx?Item=N82E16814131468[/url). I know used 7970s are somewhere around 300-325, so a used 7950 is prolly 200-225?

Anyone have a 7950 or 7970 they wanna sell for BTC?  :P

Cool I have 6 5970 on there way to OZ