You could easy pay your VPS every month and have some left with just your 7970's...

Look into using a mining program called "cgminer". With cgminer you will be able to use both your 7970's to mine Bitcoins, or any of the alt-coins.

Bitcoin is sha-256 based while Litecoin is scrypt based. But with your GPU's you can mine either sha-256 or scrypt based coins.

After downloading and extracting cgminer join a Bitcoin mining pool like triplemining.com or eclipsemc.com. Create a worker on your account. Once you have registered with a pool and have the pools url and port, as well as your worker details, go to the cgminer directory. Enter your pools information in the cgminer.conf file. You might be able to find a cgminer.conf file with the settings changed to optimize the speed for your 7970's, either way enter YOUR pool and worker details.

Now create a .bat file in the cgminer directory and enter the following:

@echo off
set GPU_MAX_ALLOC_PERCENT=100
setx GPU_MAX_ALLOC_PERCENT 100
cgminer.exe --auto-fan --failover-only
Now run the .bat file to start mining Bitcoins. Set up the Bitcoin client (wallet) on your computer. Copy your receiving address from your wallet and set the pools auto payout feature to automatically send you the Bitcoins you mined when the amount gets over the amount you choose.

If your going to put money in to hardware then you would want to get a ASIC mining device. A ASIC will mine at high speeds and only use like 45 watts compared to the 450 watts it would take GPU's. Either way, yes you can add more 7970's to the mix. Using 2 7950's with the default cgminer settings would get 660 Mh/s. When tweak it, I have hit steady speeds of 1,200 Mh/s with no issues of it overheating.
 
You can google Bitcoin mining calculator
and Bitcoin mining hardware comparison
 
On the Bitcoin mining hardware comparison search there will be a page that list the different cards and what people are averaging with them.
 
Note the Mh/s the your 2 7970's will make.
 
Now on the Bitcoin mining calculator search, go to allomoncomps(<spelt wrong for sure) mining calculator.
 
Enter your Mh/s you noted and calculate the earnings you would make hourly, daily, monthly, and yearly.
 
I'll see if I can find a conf optimized for 2 7970's... But I don't have 7970's to test with.

There is not really anywhere specific that talk about "how" to do the tweaks. At least not that I know of.

Some Example confs:

For sha-256 based coins(bitcoin)

"This should give you 670s Mh/s, then you can increase gpu-engine clock to 1180, maybe 1200 to get 720 Mh/s "
https://bitcointalk.org/index.php?topic=76228.0

For scrypt based coins(litecoin)

"Notice the notes on the right of your model card. It has basic cgminer configs for scrypt based mining."
https://github.com/litecoin-project/litecoin/wiki/Mining-hardware-comparison#wiki-ATI_AMD_GPUs

"Here's my cgminer 7970 config for scrypt / litecoins. This gets me approx 750 Khash/sec if you push the memclock to 1800 and the engine clock to 1080. This current OC config might be too high for you or you might want to push it more. On my reference 7970s the engine clock / mem clock ratio peaks at 0.6." https://gist.github.com/swhitt/5158247

"this conf will work getting 660 kh/s at 950 proc 1425 mem" https://forum.litecoin.net/index.php?topic=1794.0

I have Windows 8 x64 edition. On this page [nofollow] would I just download either one of these two and install?

cgminer-3.3.0-windows.7z [nofollow] or cgminer-3.3.0-windows.zip [nofollow]

Thank again for all your help. This is what I have done so far. I have created an account at trippleming.com. I have also created a worker account. I downloaded cgminer. Then, I downloaded MultiBit (wallet) and installed it.  I copied the link from my wallet into my worker account and have it setup to payout at 10BCT. I went into the cgminer folder and clicked on cgminer since I did not see a file named cgminer.config.file. Once I clicked on cgminer it opened up a black box. It asked me for the server. I put in stratum.triplemining.com:3334. It then asked for my worker details. I put all that in. Now in that black box that opened when I clicked on cgminer it says
[2013-06-29 11:47:09] Accepted d5432591 Diff 1/1 GPU 0
[2013-06-29 11:47:11] Accepted 4d9eab83 Diff 3/1 GPU 1
[2013-06-29 11:47:12] Accepted ea965df4 Diff 1/1 GPU 0
[2013-06-29 11:47:18] Accepted cb3c27b2 Diff 1/1 GPU 0
[2013-06-29 11:47:20] Accepted 85858bc5 Diff 1/1 GPU 0
[2013-06-29 11:47:23] Accepted d6c03aa4 Diff 1/1 GPU 1
[2013-06-29 11:47:23] Accepted eaa62e4a Diff 1/1 GPU 0
[2013-06-29 11:47:35] Accepted 7a6b941c Diff 2/1 GPU 1
[2013-06-29 11:47:37] Accepted c6040275 Diff 1/1 GPU 0
[2013-06-29 11:47:37] Accepted 2abbaa60 Diff 5/1 GPU 0
[2013-06-29 11:47:38] Accepted 0affc332 Diff 23/1 GPU 0

Can I go ahead and close this black box and create the .bat file now? Did I do everything right? Do I need to put my API key from tripplemining in anywhere? When I'm done mining for the day can I go ahead and close cgminer and close MuliBit? Is there anything I need to do before closing? Sorry for all the questions. I really appreciate you giving me a hand with all this.

Than you,
Rocky

*Edit - I now see what the above means. That was cgminer actually running. It ran for about 2 min because I didn't know what it was doing before I closed it. With the default config and no overclocks at all on my GPU's it says I am at 764 MH/s. That is higher than the config files above so should I just keep it the way it is? How do I switch to mining litecoin if I want too? How do I join a minipool? Right now when I click on minipool it says I'm the only member. I believe it said on trippleminin if you join a minipool you earn coins faster than if your by yourself.

No, a conf for litecoin will not work with bitcoin. Above I provided links to confs.. use/create one... sha-256 and scrypt are different algorithms.

The accepted lines means it is working.. The conf will just optimize your cards performance... Mine double just by tweaking the conf.

Nothing wrong will run the GPU, just to get an understanding as to how it works, since he already has them. I hope he did not buy them just for the purpose of mining. They will use as much in power and they earn in BTC, if not a bit more.


Four USB Block Erupters would yield about the same hash and run on 5v 2.0 amps.
And cost about the same as one 7970. If you are in it for fun and just want to make a few coins, cool. But if profit is your goal ASIC is the only thing that make sense.


With skyrocketing difficulty, ROI is problematic on BEs, but damn near impossible with GPUs unless you have free power. A lot of GPU miners are switching to LiteCoin, but I know nothing of Alt coins. I am just beginning to understand BTC.