Mining Hardware Comparison

[codymanix]

Hi guys, I had a look at the page on hxxps://en.bitcoin.it/wiki/Mining_hardware_comparison
but I don't understand the table fully. What does the columns "Mhash/J" and "W" mean? If "W" should mean Watts, where can I set it?

I also do not understand the column SP, which means stream processors: Sometimes there are different numbers of SPs for one and the same graphics card type?

I tried overclocking my graphics card and noticed that the memory clock does not affect mining performance at all. Is this normal?

[tunatime]

how many Mhash it gets per Watt of power the higher the better. least say that card a gets 200 Ms and uses 100w that woudl be a 2ms to 1W now card B gets 300mhs but uses 200W so in the long run card A should make more money (after power)

 are you talking about the 6950s? you can unlock the sp on some 6950s to that of a 6970

yes i haven't noticed any thing form it

[codymanix]

If MHash/J really means MHash/W why is it named MHash/J and not MHash/W?

[hollajandro]

It means Mhash/Joules.

[mintymark]

Its a speed thing. If you are buying a car, you want to know how many miles per hour it goes. You will look at the salesman and laugh at him if he says he has just driven 70 miles so it must be a very fast car. Now if he said how much petrol it had used that might be another matter.

With cards, the speed thing is how many Mega-hash per second it does. Another thing to look out for is how many Mega-hash per second it does per watt. (This is the cost to run it thing.) But wait , a watt is a joule per second so that:

1 (Mega-hash per second)  per watt is 1 (Mega-hash per second) per (Joule per second) which is the same as 1 Mega-hash per Joule.

Watts is a rate of buring of electricity, or more to the point electricity bill, where joules corresponds directly to energy used, pounds on your electricity bill.

So the time factor cancels out or is not included here, its just a matter of how many hashes you can do for a given pound on your electric bill.

In fact 1 Killowatt-hour corresponds exactly to 1000*3600 Joules. (3.6 million Joules.)

[Grinder]

With cards, the speed thing is how many Mega-hash per second it does. Another thing to look out for is how many Mega-hash per second it does per watt. (This is the cost to run it thing.) But wait , a watt is a joule per second so that:

But everybody's billed per KW/h, so the joule thing is just a detour. It's much easier to just say how many Mhash it does per watt if you want to calculate your profits.

[BombaUcigasa]

With cards, the speed thing is how many Mega-hash per second it does. Another thing to look out for is how many Mega-hash per second it does per watt. (This is the cost to run it thing.) But wait , a watt is a joule per second so that:

But everybody's billed per KW/h, so the joule thing is just a detour. It's much easier to just say how many Mhash it does per watt if you want to calculate your profits.

A Joule is a measurement of a quantity of energy. A W/h is a measurement of energy use per timeframe. 3600 kJ is a kWh.

You need to know how to compare two boards on the work they can perform with the same energy quantity.

Wold you like to see: 0.00027 Mhash/kWh versus 0.00029 Mhash/kWh instead?

[rb1205]

But everybody's billed per KW/h, so the joule thing is just a detour. It's much easier to just say how many Mhash it does per watt if you want to calculate your profits.

No, it's KW*h not KW/h.

A joule is defined as the job made by a watt for a second (W*s). If you want to know how many MHash/sec per KW you may expect, just multiply the MH/J by 1000. Or divide the MHash/s culumn by the power column, it's just the same thing.

[mintymark]

Grinder, you say
..just say how many Mhash it does per watt if you want to calculate your profits

But this is exactly like asking the car salesman how many miles he drove when you mean to say how many miles per hour the car can go at,  Its Mhash/s  per watt. Which is the same figure as Mhash per Joule. Of course, you probably know what you mean but others may not!!