Bitcoin Forum

Im looking to buy 7970's to build mining rigs for ltc... which brand or company do you recommend? and why?

I am going to be overclocking so voltage unlock or unlockable is a must... :)

Thanks!

I prefer Asus but bought Gigabyte because the Asus cards were sold out.


http://i146.photobucket.com/albums/r254/MaGNeT76/smooth7970_zps99b004dc.jpg

is that 2 cards or one MaGNeT

Thats 2 if you see by the middle it says Device 0 Device 1

GPU 0 and GPU 1 = 2 cards :)

I'm looking for voltage unlocked 7970s as well since they're great for mining alternate cryptocurrencies like LTC.

im just trying to see which brand is unlocked because i dont want a situation like im in now with my 7970

That's a really interesting topic.
I am about to buy a Gigabyte 7970 GDDR5 GV-R797OC-3GD. These are the only ones in stock unfortunately.
Is there anyone with experience with them?

as far as i know GIgabyte is hardware locked on voltage, so your OC is VERY limited to small increments... However I think you can flash the BIOS on a 7970 with a diff firmware to unlock it but im not sure... thats why im staying away from gigabyte ... on the otherhand my 7950 that is supposed to hit 582 MAX OC ... im getting about 650khs with 1025 core and 1400 mem.

But Im looking at the sapphire...
http://www.newegg.com/Product/Product.aspx?Item=N82E16814202001

I have the GV-R797TO-3GD, and they're really great cards. The triple fans are better for an open-air case, or a case with plenty of airflow. If your case has bad airflow, the temps will show it more than a stock cooler. But with the proper airflow, you can get some pretty good temps.

Mine OCs from 1100MHz to 1200MHz with no problems. The early ones were also unlocked voltage, so you might get lucky.

do you undervolt your cards? or keep them at stock voltage?

They are locked but stay cool anyway :)

Can anyone tell me what kind of PSU is needed to power 4 of these in a rig? In the specs it says:

Minimum Recommended Power System Power Supply unit 550W.

Does that mean I need a 2200W PSU? Does that even exist?

4x250W TDP = 1000W, + 150W for the cpu, ram, hdd, etc.

Get Corsair AX1200 if you want a very good PSU on that power range. Get a bigger than 1200W if your planning to get more cards, or OC them and the CPU plenty.

gotta figure out a way to Underclock the CPU... no reason for it to run high... well actually im getting a shitty cpu...

By the way i finished my list on what i am going to get it will cost about

2,246.97$
(give or take 200$ for shipping/tax)

Case: Thermaltake VN700M1W2N Black Steel / Plastic Overseer RX-I ATX Full Tower / Computer Case
147$ after shipping

http://www.amazon.com/Thermaltake-VN700M1W2N-Plastic-Overseer-Computer/dp/B008LA8BB6/ref=sr_1_2?ie=UTF8&qid=1365535783&sr=8-2&keywords=thermaltake+Overseer+RX-I

Graphics Card: 419$ ea. After 20$ rebate… + 119$ Gamecodes = 300$ (APPROX) Per card if all game codes sell…
4x Sapphire 7970 Graphics cards

http://www.newegg.com/Product/Product.aspx?Item=N82E16814202001
Processor: AMD Sempron 145 Proccessor 35$
http://www.amazon.com/AMD-Sempron-145-Processor-SDX145HBGMBOX/dp/B0040BPHJO%3FSubscriptionId%3DAKIAIAA4MWUJXHBYFRNQ%26tag%3Dsquid1633810-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D165953%26creativeASIN%3DB0040BPHJO

Power Supply: OCZ OCZ-ZX1250W ZX Series Modular Power Supply - 1250W, 80 Plus Gold, 140mm Fan, Active PFC, SLI & CrossFire Support $239.99 After Rebate $219.99

http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=7213995&CatId=5115

RAM: Crucial Ballistix Sport 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10600) Desktop Memory Model BLS2KIT4G3D1339DS1S00 $68.99

http://www.newegg.com/Product/Product.aspx?Item=N82E16820148543

Motherboard: ASRock 970 Extreme4 $99.99

http://www.newegg.com/Product/Product.aspx?Item=N82E16813157262&Tpk=ASRock%20970%20Extreme4&IsVirtualParent=1

Total: 2,246.97$

That case has a rebate at Newegg, which makes it a bit cheaper there, fyi.

http://www.newegg.com/Product/Product.aspx?Item=N82E16811133194

Few thoughts/comments:

- If this is a mining rig, why are you getting a case? Run it without a case and the GPU's will run cooler. Also, not sure how you would fit 4 cards on that motherboard if the motherboard is in a case.

- Your way to high on what you will get on the game codes. The going buy it now price on ebay for both codes combined is $40 - $45.

- Go with a Seasonic PSU or a rebadged Seasonic PSU (XFX, etc) over an OCZ PSU. Pretty much the same price but a lot higher quality.

- You don't need 8 gb of memory. 4gb or even 2gb will do.

- You need to pick up some PCI-E riser cables. Go with the powered kind or convert the passive ones to powered yourself.

Hope this helps.

HIS IceQX2 purely because they are cheap yet still come with a fantastic heatsink/cooler

HIS will take a month with 3 weeks if it sitting in the RMA warehouse if the card dies under warranty.
XFX has a faster RMA turnaround but not great.

Do go voltage unlocked and consider the warranty..  If the card dies, the warranty is what will matter.
Google bitcoin mining comparison and read the wiki.  If it is a fast BTC card its usually a fast altcoin card but you need to search 1st.

Of all the cards I own the 2 most impressive models are my MSI 7950s (1st revision with the 6/8 connectors - no longer made) because they were voltage unlocked and also my Diamond reference 7970s.  This surprised me as I had never bought a Diamond card before and considered them crap.  Of all the 7970s I've used these stay the coolest and are the most stable using low voltages and overclocks.  Beating even Sapphire and Gigabytes (the new Gigabyte 7950 and 7970s suck BTW - haven't found 1 of them that can go past 1150 on 1.25v - they must have bought the cheap garbage binned chips).

Why not Asus Ares ???  :D  A big bomb .. althought very expensive

That would be about as smart as buying a 5450 and trying to hash with it.  Both are out-layers in the hash/price ratio - neither would be a good for returns.  Of course it might turn on the ladies  :D

I got two powercolor 7970 v3, and I can confirm its voltage is unlocked.
but I can only get them stable at 1.05v mining at 1010/625 at 600M/s

I guess I haven't checked the other warranties, but Diamond is 1 year - had a 6990 die completely on me, and they bounced RMA coverage for it.  We're not talking dead fan here due to abuse - just died one day.

I guess I hadn't really looked into detail on these - figured all reference boards had the same warranty, like everything used to!

Are you in the US?  My retail Diamond 7970 says 5 years and I registered it on day 2.  Of course what the box says and real world are 2 separate things, but I am just 10 miles from their CA headquarters and can raise hell :P

I just got one yesterday and I am running the Gui Miner from 50BTC. I am getting 604MH/s on stock settings. I plan to get cgminer running and do some tweaking later.

I prefer stock(reference) hardware with custom cooling(I prefer Accelero) and/or some BIOS/hard/soft mods.
Usually it takes ~4h to figure out the best solution for each particular piece of harware.

the sapphire dual-x's are unlocked (core and memory voltage).

I get about 690-720khash out of it for scrypt.

I also get about 680-700 mhash out of it for sha.

even with fans at 100% it is VERY quiet compared to the gigabyte cards.

and it even comes with an HDMI cable.... was a nice surprise

I'm using 2x Sapphire 7970 and one seems to have the voltage at 1.137 and the other at 1.2. The model numbers are the same. Is one locked? Weird

just found this  http://www.legitreviews.com/article/1805/14/

sounds VERY promising for these cards.  


Our friends at AMD were kind enough to send over the new BIOS file and the WinFlash tool that was needed to get the job done. AMD plans on releasing an executable of this BIOS to the public, but the one they sent us to distribute was having a few issues on some boards we tried it on.

With the new BIOS installed we were shocked to see the max clock settings were now 2000MHz on the core and 2500MHz on the memory! Houston, we are not clock limited any longer!

That article was written in December of 2011.