Radeon HD 7970?s and overclocking - mining machine madness

Hi all.

It turns out that I have two of these older cards sitting in a box from my old mac g5. I know they are good cards.
AMD 7970, 3GB of DDR5 Memory, with a 384-bit memory bus. Circa 2011 to 2012.
I was cleaning out my drawers this holiday and was thinking of selling them on eBay, but was curious if anyone had any bright ideas.

Is it possible to add them to my gaming computer (which I'll be re-branding as my mining machine) - I have cheap power, don't want to talk about that here.
As for the machine and capabilities, I'm a software guy. How hard is it to add additional cards (assuming I have the slots and power cables) into the machine?

The gaming machine is an windows 10, I7, pretty peppy mother board and so on with two GFX cards already. Lots of cooling, very hefty power supply, etc.

There isn't much room left in my case, but...

The pict of my cards are basically the same ones in this article:
https://www.pcworld.com/article/250644/how_to_overclock_your_graphics_card.html

I was wondering if anyone can help me with the thought of adding these two additional cards to my existing machine.. making it have 4.
I was told there are additional risers and other possibilities?

Or, should I just sell them on eBay??

Thoughts?
Thanks, Howie

adding the card would be pretty straight forward. You probably don't have another pcie x16 slot, tho. So you'd need to get a riser card for it to run. Those are usually about $5 for one. They are pcie 1x to 16x. They do use USB 3.0, but for mining, that's plenty fast enough.

Now, using that card for mining, I don't know. I currently have a Radeon 7770 card with 4GB DDR5 and I have about 1MH/s. But I'm currently using that card in my main system, so it's a little slower atm due to other loads.

Based on some quick googling, the 7970 will get around 12-13MH/s. I would sell them for a few reasons. The DAG size for both ETC and ETH is around 2.40GB. Those cards will only mine Ethereum for a few more months. After the 3GB DAG is hit, there resale value will drop dramatically on eBay, so get the higher sales while the getting is good. Take that money and buy a newer card, the RX480/RX580 are best for mining. The 4GB versions are said to be good until end of 2019. Grab an 8GB version if you can.

As for risers, these are the ones I'd recommend without doubt. I ordered another brand and had to return them, wasted 2 weeks of my time. These ones I've used 5/12 so far and haven't had one DOA. The build quality is excellent. They have smaller packs if you don't want a large 12-pack.
http://amzn.to/2zIMtCU

If you go the riser route, the cards won't fit in your computer. You'll have to mount them outside. If you're building a miner with 4 cards, I assume you're not using a traditional ATX case anyway.

mike said:

Based on some quick googling, the 7970 will get around 12-13MH/s. I would sell them for a few reasons. The DAG size for both ETC and ETH is around 2.40GB. Those cards will only mine Ethereum for a few more months. After the 3GB DAG is hit, there resale value will drop dramatically on eBay, so get the higher sales while the getting is good. Take that money and buy a newer card, the RX480/RX580 are best for mining. The 4GB versions are said to be good until end of 2019. Grab an 8GB version if you can.

As for risers, these are the ones I'd recommend without doubt. I ordered another brand and had to return them, wasted 2 weeks of my time. These ones I've used 5/12 so far and haven't had one DOA. The build quality is excellent. They have smaller packs if you don't want a large 12-pack.
http://amzn.to/2zIMtCU

If you go the riser route, the cards won't fit in your computer. You'll have to mount them outside. If you're building a miner with 4 cards, I assume you're not using a traditional ATX case anyway.

Click to expand...

Well I guess this 7950 and r9 280x (another 7950) are going to be going up for sale here. Thanks for the info Mike, would have never thought about the DAG size effect, have not been mining for ~4 years now and this group had re-sparked my interest.

So if anybody is in the market? Cheers!

Well, is there any way to get it to be used for mining a different coin? Would it be worth it to use it for XMR or something like that? I know some are CPU only, though. That's why I ask.

I'm currently doing CryptoNight and X11Ghost. Not sure if that's the best or what not for my hardware. Still getting my toes wet in all this.

neurocis said:

mike said:

Based on some quick googling, the 7970 will get around 12-13MH/s. I would sell them for a few reasons. The DAG size for both ETC and ETH is around 2.40GB. Those cards will only mine Ethereum for a few more months. After the 3GB DAG is hit, there resale value will drop dramatically on eBay, so get the higher sales while the getting is good. Take that money and buy a newer card, the RX480/RX580 are best for mining. The 4GB versions are said to be good until end of 2019. Grab an 8GB version if you can.

As for risers, these are the ones I'd recommend without doubt. I ordered another brand and had to return them, wasted 2 weeks of my time. These ones I've used 5/12 so far and haven't had one DOA. The build quality is excellent. They have smaller packs if you don't want a large 12-pack.
http://amzn.to/2zIMtCU

If you go the riser route, the cards won't fit in your computer. You'll have to mount them outside. If you're building a miner with 4 cards, I assume you're not using a traditional ATX case anyway.

Click to expand...

Well I guess this 7950 and r9 280x (another 7950) are going to be going up for sale here. Thanks for the info Mike, would have never thought about the DAG size effect, have not been mining for ~4 years now and this group had re-sparked my interest.

So if anybody is in the market? Cheers!

Click to expand...

Yup, Like @neurocis said above, my two cards also will go out for sale this weekend on eBay. Thinking about it, yes, two old cards which are end of life for mining vs one much healthier card (ie the RX480/580) is very good thinking. It will perform better, longer and use less power then quantity two 7970's.

Kori, I actually have one more empty PCIe slot on my mother board, but it is way at the bottom and there is not much room left in the case anyway. Even if I could fit more hardware in there, I would expect heating issues due to lack of circulation. I have been researching the risers, and was going to purchase a few on amazon today ... based on Mike's experiences, I am going to purchase the risers Mike suggested above.

As for the mining server, I have decided that I am going to take this whole beast apart and build an open air unit. This gives me more flexibility, the ability to put in a better power supply and gives me more growth/expanding possibilities into the future.

I'll post pics of the new rig once it is all put together - it will start as a new years weekend project.

OMG, this is also becoming an obsession.

Thanks for the replies above - and have a HAPPY AND HEALTHY NEW YEAR!!

Well, a small update - I've been mining ETH on one of my two rigs for the last few weeks.
They are very stable with overclocking and the latest beta radeon driver for windows at 8.5 Mhash each through both Claymore and Minergate Gui.

My only issues with these cards:
a) fans need to be running at 65-75% to keep cool - that makes them very noisy
b) they don't seem to run too warm - around 50C at 65% fan
c) they only have 3gb ram, s even with the DAG ok now, in a year, they will not be as effective for ETH.
d) uses around 220 watts each whilst mining ETH. compred to my RX580's which use around 1/2 of that.

With 750 watt ps, all runs great.

I put them on EBAY Monday and have sold one already and have a bid on the other.
I'll pick up another RX580 8gb when I can to replace them.