Re: PhoenixMiner 4.7c: fastest Ethereum/Ethash miner with lowest devfee (Win/Linux)

2Gb,4Gb DAG fix, need atleast 1 GPU large enough to generate DAG.

Recently realized in my farm that my 470 4Gb rigs, which were all 6 card setups at the time, were not generating the dag any longer for ETC and then soon after ETH dag approached whatever level it was that pushed my system over the limit. After a day of wondering what to do, I realized a 470 rig I have with 1 8Gb 580 in it was working fine with the other 5 cards being 470 4Gbs. I took apart one of my 580 8Gb rigs and replaced a card on one of the 470 rigs. Mined perfectly fine. Did this to the whole farm and split the gpus essentially so every 4Gb rig has atleast 1 8Gb card in it. As for now this works no issues. I have a p104-100 rig with 1 470 4Gb in it and same thing, generated dag and mines.

I tested this on 2Gb R7 200 gpus and works perfectly fine. Card generates the dag as long as the system has one available card that is able to fit the dag on it. This is identical to how the 470 rigs are operating.

The same goes for 470 4Gbs with rx 5700s and the same with the R7 200s with the rx 5700s.

It sounds like 4GB isn't enough for the DAG since the current DAG is 3.27GB for ETH or 3.34GB for ETC.
RedPandaMining recently posted a video on his Youtube Channel.
https://www.youtube.com/watch?v=xRIX5mpVntk

It would be awesome if it worked on 3gb Nvidia cards, but from what I have seen its only a fix for AMD cards with 4gb and below running on windows. I setup a windows box with a GTX 1070 and a couple gtx 3gb 1060s with no luck, then I tried a mixed mode setup with an 8gb AMD card as the main GPU with no luck as well. I figured it would not work with Nvidia cards below 3 gb, but I wanted to try it out for kicks. If anyone else tried and had luck let me know.

your discussion is seriously weird. it is impossible to load >3gb array into <3 GPU memory whatever tricks you may perform.

DAG - directed acyclic graph

"The Ethash algorithm expects the DAG as a two-dimensional array of uint32s (4-byte unsigned ints), with dimension (n × 16) where n is a large number. (n starts at 16777186 and grows from there.) Following the magic number, the rows of the DAG should be written sequentially into the file, with no delimiter between rows and each unint32 encoded in little-endian format."

"...calculating the PoW (Proof of Work) requires subsets of a fixed resource dependent on the nonce and block header. This resource (a few gigabyte size data) is called a DAG. The DAG is totally different every 30000 blocks (a 100 hour window, called an epoch) and takes a while to generate."

If you check out the comment I was responding to it mentioned that they are able to get 2 gb AMD cards to work provided they have one card in the mining rig with 8gb for the dag to populate on. I took them for their word and tried it with Nvidia but apparently it only works with AMD cards. I suppose I could find a 2gb AMD card and mix it with a 8gb card and see if what they say is true, but I do not really see what they would have to gain from making something like that up.