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Title: 2x6950 or 1x7950? Post by: Elmojo on February 10, 2012, 12:06:18 AM Hi All,
I'm just getting into BTC mining, and need to upgrade my video card. My current PC is a Core i7 930 @ 4.0Ghz, 12GB RAM, SSD, and a GTX480 (factory water cooled). My PSU is a Corsair HX1000, so no worries there. I was originally planning to upgrade to a 7950 with a waterblock, which will run me just under $600 and from what I've read should net about 600Mh/s when overclocked and tweaked. Today, I saw that sunbreak is selling a bunch of new 6950s for ~$220 each plus shipping. He claims they will run at 360-400Mh/s each, for a net of roughly 700-800. Later today, I ran across a post reminding me that a 5970 will rock about 750 Mh/s. I can get one used for ~$450, and add a water block for about $120 if I choose. I'm so confused! lol Can anyone offer advice? Am I better off mining with 1x7950, 2x6950, or 1x5970? My power costs are roughly $0.12/Kwh, and my machine stays on 24/7 already. I have 2 PCIe slots (1 currently open), so I could leave my GTX480 in there and install the 'mining' card, if that's an option. Any advice appreciated! -Elmojo Title: Re: 2x6950 or 1x7950? Post by: Lazer on February 10, 2012, 02:42:38 AM First things first, u dont need an overclocked cpu for mining. in fact you may wanna underclock while mining it to save some power.
go with the 6950s they have a better performance to energy consumption ratio Title: Re: 2x6950 or 1x7950? Post by: Elmojo on February 10, 2012, 02:51:54 AM True, but this is my primary rig, used for Editing, CAD, gaming, etc...
It already runs 24/7, so the only extra power use will be from the GPU. Do you have any data that shows those cards being more efficient? Title: Re: 2x6950 or 1x7950? Post by: Lazer on February 10, 2012, 02:57:52 AM Do you have any data that shows those cards being more efficient? https://en.bitcoin.it/wiki/Mining_hardware_comparison look at Mhash/J per card, the higher the number the better Title: Re: 2x6950 or 1x7950? Post by: Elmojo on February 10, 2012, 04:14:27 AM I've stared at that page several times, and still can't seem to make heads or tails of it!
There seems to be several metrics for what makes a "good" mining card. Based on your criteria, the 6950 is actually the worst Mh/J of the three, or am I missing something? Model Avg. Mhash/s Mhash/J Mhash/s/$ 5970 655.83 2.01 0.90 6950 360.62 1.8 1.44 7970 625 2.89 1.13 <-Overclocked 7950 should be within 15-20% of this If I'm interpreting the chart correctly, the 7970 is the clear winner on efficiency, while the 6950 is the best hash/$. Taking into account the lower cost of the 7950 compared to the 7970, it looks like it (7950) is the best choice. Of course, that chart lists the 5970 as a ~650 hasher, while I've seen a couple references to them being more in the 750 range. That could make a difference too. Somebody please set me straight here! |