Bitcoin Forum

I have been looking around and I can not decide between these cards. If I want the best (raw power) card for Bitcoin...would it be the 6950. I am finding a lot of mixed reviews.

ATI 5850
ATI 5870
ATI 6950

6990 for raw power. 5830 for cheap redundant power.

Okay, so the 6990s are a $$$$. If i get one 6990, will it be better that 3 5850s?

Have you tried this site?
https://en.bitcoin.it/wiki/Mining_hardware_comparison

just found out about that site about 5 minutes ago. Thanks

Although the poster expresses a preference for raw power, anyone else considering a new bitcoin mining rig should optimise three separate features...

1. maximum MH/sec per GPU card - fewer GPU cards mean fewer motherboards, CPUs, and power supplies, software configuration, and monitoring effort.

2. minimum purchase expense per card - with mining difficulty exponentially increasing due to exponential growth of total network hashrate, its possible that certain expensive mining rigs will not payback their purchase price after subtracting gains from selling off the used components later.

3. minimum power consumption per card - this ongoing cost determines the point at which bitcoin mining ultimately becomes unprofitable on a cash flow basis.  Lower power consumption per card makes it easier to cool the card and also to overclock it.

The Radeon HD 6990 is optimal only for criteria #1 above.  The owner of the famous 48 GH/sec mining rig featured on YouTube says that he is "upgrading" his vast number of 6990 cards with 5830s as he can obtain them.  Why?  Because of criteria #3 above.

I chose to construct my 1200 MH/sec rig using three case-less motherboards with two overclocked HD 5770 GPU cards each.  The HD 5770 cards were the most optimal for me using these criteria considering the limited choices at Newegg in the USA at the time of purchase.  The power drawn by the shared UPS is 850 watts.

x2.... I'm running a case less mobo now with 2 5830s. Soon to be 3 as soon as my cables show up. Should also help out with the heat issue.

Why not a 6970?

This card is looking good to me  http://www.newegg.com/Product/Product.aspx?Item=N82E16814161349. I am thinking about 4 a system.

I have 2 x 5870's (2 GPU's) and 2 x 6990's (4 x GPU's) in two rigs, all running standard. I have found the 5870's have performed at a relatively constant 350 M/H whereas the 6990's fluctuate somewhat between 280-350 M/H due to temperature i.e. AMD Overdrive decreases the clock speed on two of the 6990 GPU's periodically. I have not ascertained whether I simply have a substandard 6990 card, or whether the configuration is not sufficient to dissipate the heat on standard for two cards side by side. That said I get a minimum of 1.1 G/H for the 6990 rig even when it has auto clocked down.

For raw power, the 6990 produces the desired results, even if for me it has not necessarily been the optimal result.

ATI Radeon HD 58xx series are better than 6xxx series at mhash per cost of card, that's why they are sold out everywhere. Being able to ever break even on new card by mining is very iffy now. If you are going to be gaming and just hobby mining, you should get whatever card suits your gaming needs.

People keep saying that the 5XXX are better than the 6xxx(only for bitcoin).  I guess I'll try a 58xx Rig. If i can find the eq.

So what card will give me the best mhash--forget about price?

I believe most of these are average overclocked speeds but it will give you an idea.
https://spreadsheets.google.com/spreadsheet/ccc?key=0AsSwOT3E1XTGdGtpa1BQcmJLN2x6TG1MRmxzb29BeFE&hl=en_US&authkey=COWC8toK#gid=0

Best Mhash will come from a 6990x2, but as the above poster said, you need to consider a lot more than just that.  The best mhash/watt is from the 5830.  I chose the 6870 because I got a good price and I thought it was a good mhash/$.  If you re severely limited with space then you go for a more powerful (and expensive) care. If you have plenty of space and slots, then you try to go for the best mhash/$. 

The 5800's and 6800's are pretty good sweet spots for all of those statistics.

Okay, good point. I am about to buy my first card withe Bitcoin i have been saving. I am in the $200 rang. I guess the 5830 is a good place to start.
 

Depends on if your rig is soley for mining. If you plan on gaming as well, go for a 6950 or 6970. If you want to build a 24/7 mining rig, go for the 5830 or 5850/70. 5870 will actually mine a little quicker than the 6970 based on the stream processor count.

since i bot online games i will get the more powerful 6970. knowing that i can later use it in another machine to bot with

I think the most bang for your buck is 5970.

Yeah, I keep seeing that.....Okay, So 5 rigs with 4 5850s each. I think that is the past I'll take.

I think the 5850 has the most bang for your buck.

After choosing your graphics cards, its important to now consider the number of rigs.  As with GPUs, there are several independent features to optimize ...

1.  Fewer motherboards, i.e. five rigs, mean fewer disk drives or USB sticks to contain the operating system, fewer CPUs, fewer network cables, less shelf space, and easier hardware monitoring - in that you either have to hook up a monitor, mouse and keyboard to a motherboard in order to work on it, or using Linux, e.g. linuxcoin, one can ssh into the rig to see all the attached graphics cards.  Fewer motherboards may mean fewer power supplies, but gaming-style power supplies can be more expensive when capable of powering say four overclocked 5850s - maybe 1200 watts per single power supply or simply two less expensive power supplies per motherboard.  Motherboards having four PCIe slots are more expensive than those having say two PCIe slots.  See the forum thread for mining rig photographs for ideas on how to cool packed GPU cards, or to move them away from the motherboard using PCIe extension cables.

2.  More motherboards, i.e, ten rigs with two 5850s each, on the other hand may be more expensive in total than the alternative (1) above, but they are far easier to cool - as the cards are twice as far apart and the GPU fans have a much better inflow.  Commodity motherboards permit the use of much less expensive power supplies - say 600 - 850 watts apiece.

3.  Consider whether  to enclose the rigs in cases.  Operating without a case may violate certain consumer protection laws against electronic emissions but the practical reality is that many miners, and myself do so.  Cases very much restrict airflow, but compensate somewhat by adding fans.  If noise and component clutter are not an issues, consider operating without cases.  Again, one can get many ideas from the mining rig photos posted in the hardware forum.

Each rig will have 4-5 video cards with a usb drive. I am thinking about 5-10 rigs. Depending on how fast i can sell the coin. if i keep selling a t a good step, I'll keep adding rigs. I have most of the EQ now so this will save on $$$.

I did not think about an open case. Might be a good idea. I'll let you know.
Thanks

I really like my 6970's.  They perform very well, and I have municipal power that I don't spend big money on power.

That's a little ambitious. If you have built computers before and your confident then I say go for it if you have the money. However if you have never put a rig together before I HIGHLY recommend only purchasing one until you make it fully operational. That way you can back out if you change your mind

got my 6990 at :) from http://bmedeals.webs.com but taken two weeks to get ..... but at least im not one those guys having 100 something back-order waiting list..... like on amazon.. and other sites.. so crazy and hard to get theses cards ... i feel lucky! time to mine !

Yeah, It is hard to get ATI cards now. Been looking the last few days.