Ideas on new GPUs?

[ATC777]

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! 

Regards,

--ATC--

[1715257636]

1715257636

[1715257636]

1715257636

[davecoin]

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

[crazyates]

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.

[ATC777]

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! 

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

[ATC777]

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.

[Jack1Rip1BurnIt]

I would pass on the 6870.

[ATC777]

I would pass on the 6870.

Explain

[foggyb]

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.

[notaek]

Yeah I would probably go 7950

[ssateneth]

I would pass on the 6870.

Explain

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.

[Luno]

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

[crazyates]

I would pass on the 6870.

Explain

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.

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.

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.

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?

[ssateneth]

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

[foggyb]

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.

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?

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.

[fcmatt]

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.

[notaek]

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.

[crazyates]

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 vs $360. I know used 7970s are somewhere around 300-325, so a used 7950 is prolly 200-225?

[ATC777]

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

[YipYip]

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

Cool I have 6 5970 on there way to OZ