Bitcoin Forum

I have made my mind to buy three 7950 . should i go for the gigabyte one or the Sapphire   

Gigabyte  7950  :  http://www.amazon.com/Gigabyte-Mini-Displayport-PCI-Express-Graphic-GV-R795WF3-3GD/dp/B007581QHG/ref=sr_1_1?ie=UTF8&qid=1365790693&sr=8-1&keywords=hd+7950

few  days ago it was $299 currently out stock other seller are selling at $350+ . so have to wait i guess

Sapphire   7950  :  http://www.amazon.com/Sapphire-Radeon-PCI-Express-Graphics-11196-16-20G/dp/B0098HW1HG/ref=sr_1_2?ie=UTF8&qid=1365790693&sr=8-2&keywords=hd+7950

current price  $320

what you think? which one will perform better ? does the Sapphire card have any vrm temparature issues ?

so should i buy the Sapphire or the gigabyte one . incase its gigabyte i need to wait for the price to be under $330(my  maximum budget per card)

thanks in advance

I've got 2 of the Sapphire cards http://www.amazon.com/Sapphire-Radeon-PCI-Express-Graphics-11196-16-20G/dp/B0098HW1HG/ref=sr_1_2?ie=UTF8&qid=1365790693&sr=8-2&keywords=hd+7950

Temps on both are great, but the fans are quite noisy on full blast!

thanks for the reply . noise will not be a problem .

How much khash do you get ?

To be honest I don't use the for LTC mining, but mining other Scrypt coins they hashed at about 500 K/hash each with intensity set @ 13

With a bit of tweaking you'd probably get far better speeds!

If it's any help I used these flags for CGMiner --shaders 2048,2048 --intensity 13,13 --worksize 256,256 -g 2  --thread-concurrency 8000,8000 --temp-target 60,60 --temp-cutoff 78,78

I have run 3 variants of the 7950 cards:

Single Fan Sapphire 7950  - http://www.newegg.com/Product/Product.aspx?Item=N82E16814202030

Dual Fan Sapphire 7950 - http://www.newegg.com/Product/Product.aspx?Item=N82E16814202006

Tri Fan Gigabyte 7950 - http://www.newegg.com/Product/Product.aspx?Item=N82E16814125414

I find that the Gigabyte is easiest for achieving 600 KH/s when overclocked to 1000/1450.
The other two Sapphire cards I had to push up the power % to 10% to get 600 KH/s.

That also may mean that the Gigabyte card draws more power. They do require a single 6 pin and a single 8 pin to power, vs the other two Sapphires that only require 2x 6-pin.

EDIT: And my settings on all cards are the same (I use afterburner MSI, works perfect):

Core: 1000
Mem: 1525

And on CGMiner:

--lookup-gap 2,2 --thread-concurrency 21712, 21712 -I 20,20 -w 256,256

If you want to ONLY use CGMiner to overclock, and not afterburner - use this:

--lookup-gap 2,2 --thread-concurrency 21712, 21712 -I 20,20 -w 256,256 --gpu-engine 1000,1000 --gpu-memclock 1525,1525 --temp-target 75 --auto-fan

(Note: the above settings on CGMiner are for two GPU's, adjust for 3)

Sapphire is generally more reliable in my experience in dealing with 1000s of ATI cards since 5xxx series.

Reliable as in they have a low failure rate or reliable as in the card have little variance between them so settings for one will be similar for all.

If it's failure rate what sort of wastage do you see? Very interested in this as it could make a massive difference if mining at scale!

Cheers
Trommie

I use two sapphire and it gives 1.1k

Reliable as in failure rate is lower than other brands.  DOA rate is also quite low from what I saw.  Hard to put a percentage on it as I never kept a list but out of box DOA was probably 1-2 out of 100, and failure within a year ranged, I'd say 3-7 out of 100.  Not all failures were a result of the manufacturing, not everyone was as *ahem* skilled at building water cooled systems as others. ;)

Sapphire 7950, http://www.newegg.ca/Product/Product.aspx?Item=N82E16814202030

I used to run it reliably at 530 kH/s then bumped it to steady 580kH/s +

thread-concurrency 21712 , worksize 256, intensity 20, vectors 1. @core 1100, @memory 1375, power target +10%
With Asus gpu tweak, I manually configured the gpu fan curve to keep the temps right and a bit cooler than default.


I also had an XFX 7850, but it was barely crossing 350kH/s.

I love the 3 fan design of Gigabute  ;D

Thank you. Stats like that are always useful to know  




Oh dear! :)

Not a problem! :)

I also know lots about other components, so feel free to ask away.