Bitcoin Forum

Hi, i am looking to build a new mining rig from cyberpowerpc. Before you say it, yes i have been building my own pc since high school a decade ago but just dont have the time now nor kept up with the latest tech, so rather paying a little extra to have one shipped to me.

I understand 5870 is still the most popular, unfortunately the price has gone through the roof making this card impossible to obtain. I did my research and have come up with 3 competitive cards but not sure which one is the most efficient to pick, please help.

1) 5850: $220
2) 5950: $260
3) 5970: $350

I plan to use the GigaByte GA-890FXA-UD5 AMD 890FX Chipset Support CrossFireX as the mobo, from my understanding it can support up to 3x graphic card? At least cyberpowerpc let you pick up to 3 graphic cards with this mobo.

So which do you guys think is the best way to go? in term of value+performance/resale value in 1-2 years etc... I will be getting 3x of the chosen card.

Also cyberpowerpc has the below setup option, which one should i pick as a dedicated bitcoin mining rig?

  A) Xtreme Performance in SLI/CrossFireX Gaming Mode Supports Single Monitor
  B) Non-SLI/Non-CrossFireX Mode Supports Multiple Monitors

Thank you

https://en.bitcoin.it/wiki/Mining_hardware_comparison (https://en.bitcoin.it/wiki/Mining_hardware_comparison)

Do note that most of the values from above are from overclocking.

As far a resale goes, who knows what it'll be like.

Go for the non crossfire, since crossfire hinders mining across multiple gpu.

I have 2 6950s one unlocked to 6970 and one not unlocked.  Both are running at ~ 900 MHz and are within 3% of each other performance wise so there is not much difference.

 

3 6950

thanks guys, i have a feeling 6950 is the way to go. 

dinzy, are you saying 6950 and 6970 dont have much performance difference in term of bitcoin mining?

Hey here, are you sure your unlocked 6950 is

a: equipped with the extra shaders (verified through GPUZ)

b: not throttling?

I assume that you do have the shaders unlocked, and not just an unlocked bios flashed with fused shaders, but the second point is more my concern. I have heard of a lot of people who have unlocked the shaders, and found they also needed to bump up the power level via CCC or other at least a few percent (its the -20% ---> +20% "Power Control" slider in ccc)

Yeah for for the 6xxx series, you'll still have a fairly current gaming card to use or sell when your mining days are done, plus they're a bit more energy-efficient and cooler than the 5xxx series.

You can put multiple cards in the same system for mining, just don't Xfire them until you want to play some games. I know the 6970's are a little more expensive than the 6950's, which you can flash, but you really do get what you pay for. For example, the cooling on the 6970 is improved over the 6950, the fan is actually different, etc.

If you're planning to get three of them, then you need at least 850W of a gold standard PSU, such as the Corsair Ax850. If you use a single ram stick, downclock your CPU, and don't hook up more than a single optical and hard drive, you'll be able to run three 6970's when it is brand-new. But PSU efficiency tends to drop over time as the hardware ages so potentially you might have trouble running that setup in a year or two. Probably better to go for the Ax1200 for extra headroom to give you no issues for the life of the system. But this is the one component of your whole system you do not want to skimp on.

Yes.  It looks like the shaders do not give you anywhere near as much boost as clockrate. The 6970 will guarantee you 880 MHz but most 6950s should hit that.  That being said, some cards are unlockable so it would be better to get those since you would probably have 10-15 MH/s more per card.  3 of those will add up so that is an important consideration. 

My unlocked one is a MSI twin Frozr II and it is certainly unlocked and not throttling.  It throttles when I go over 900 MHz.

The locked one is an HSI one from newegg, the cheapest one for 2GB.  The unlock flash "works" but does not do anything.  I think they just shorted a line to ground so you cannot actually write to the BIOS.  My guess is that all cards are unlockable, but the most recent ones have flashing disabled. 

Do you live near a Fry's?  They have a generous return policy and typically have an older stock.  You could probably buy 3 of the twin Frozr II OC editions and unlock them to 6970 shaders and overclock to ~ 900 MHz

That is only applicable in gaming. In mining, the shaders DO make a difference. By the way, they did not short a line to ground. Those cards can't be unlocked because they physically laser cut the die. Thus, there is no way to enable those extra shaders through software.

god damn this is so hard, i totally cannot make up my mind.  The 3x 6950 barebone comes out to be around $1500, i might as well just get the dual 6990 then for $2000.  This is the latest config i have, what do you guys think? worth it?

    CPU: AMD Athlon™II X2 255 Dual-Core CPU w/ HyperTransport Technology [-20]
    2X VIDEO: AMD Radeon HD 6990 4GB GDDR5 16X PCIe Video Card [+734] (Major Brand Powered by AMD)
    MOTHERBOARD: Asus M4A87TD EVO AMD 870 Chipset CrossFireX Support DDR3 Socket AM3 ATX w/ 7.1 Audio, GbLAN, IEEE1394a, USB3.0, SATA-III, RAID, 2 Gen2 PCIe, 1 PCIe X1, & 3 PCI [+12]
    MEMORY: 4GB (2GBx2) DDR3/1600MHz Dual Channel Memory Module (Corsair or Major Brand)
    HDD: 500GB SATA-II 3.0Gb/s 16MB Cache 7200RPM HDD [-16] (Single Hard Drive)
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$2100 shipped