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I'm buying a PC with gfx cards just for hash cracking.
I have a budget around $2.5k (+/- $500). I read about HD7990 that this one like 2x7970.
1. Which is the better: 2x7990 or 4x7970?
2. Which motherboard supports 4 video cards? I read that the usual motherboard supports only 3 GPUs. And I read there, at this forum about PC with 8GPUs. But it was a server motherboard.
Thanks
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02-05-2013, 12:52 PM
(This post was last modified: 02-05-2013, 12:54 PM by themask.)
You better have 4x7970. 7990 is not an official card, it take huge amount of power and take 3 slots. (Tests showed that it slower than 2 separate card as the 7990 is basically just 2 7970 crossfired)
Lot of motherboards support 4 Vga, if they have enough PCI-E slots. (AMD driver is limited to 8 GPU per Motherboard)
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Thank you for fast reply.
Great! Will buy 7970.
As for the MB, could you give me advice in model. For example "Asus P8Z77-V LK" have only 3 PCI-E... or not?
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GA-990FXA-UD7 - cheap and works okay.
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02-05-2013, 01:37 PM
(This post was last modified: 02-05-2013, 01:39 PM by random2.)
ASUS P8Z77-V PREMIUM can be used as 4 PCI-E x8 or 2 PCI-E x16. But if I will use it as 4 PCI-E x8 how it will affect the speed?
Also about model of HD7970. Does it matter? I was advised to Gigabyte.
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It won't affect the speed even if you use 1x since cracking require little bandwitch (compared to 3d)
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Okay. It's good. So the last question about GPU. "Gigabyte" or it does not matter? What do you suggest?
P.S. as I read, other components (HDD, RAM) may be the cheapest, right? Attention should be given to power supply unit and cooling system?
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(02-05-2013, 02:00 PM)random2 Wrote: Okay. It's good. So the last question about GPU. "Gigabyte" or it does not matter? What do you suggest?
P.S. as I read, other components (HDD, RAM) may be the cheapest, right? Attention should be given to power supply unit and cooling system?
It don't matter. It only matter if you going to OC them. I personally use Sapphires.
Power-supplies and Cooling are very important.
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if you are going to put the GPUs into a case, then you should probably buy reference design cards.
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02-06-2013, 12:28 PM
(This post was last modified: 02-06-2013, 04:51 PM by random2.)
(02-05-2013, 02:08 PM)themask Wrote: I personally use Sapphires.
How many GPUs do you have? Also 4?
(02-05-2013, 02:08 PM)themask Wrote: Power-supplies and Cooling are very important.
Will there be enough 1000W-power supply?
epixoip Wrote:if you are going to put the GPUs into a case, then you should probably buy reference design cards.
You mean a specific model of video card?
I read reviews about HIS, it has a good cooling system.
Also Gigabyte has 3 fans (others has only 2 fans).
