2015 Hardware
#1
Question 
First off I have NOT found anything on thing on this sorry if I am wrong.
I wanted to build a system with 4 to 8 7990 it just depends on the total cost. I know that a single 7990 gets about 18mh/s. How much can I overclock it if I put a full water block on it and have a quad radiator? I need help finding a case and mobo or rack that can support this. I thought about the corsair 900D of the H1. I know that the Tyan racks are popular but they are too expensive for now. The mobo needs to support up to at least 6 pci 3.0 x16 for the 7990's. Thank you for the support and sorry again if this is all super stupid and easy I just dont want to mess up. And yes I viewed the forum on case and cooling selection.
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#2
You won't be able to have more than 4 hd7990 (8 gpus) on a single rig. If you can watercool and have a good leakproof loop, it's going to be a great cracking rig. You will have to test it yourself to know how much you can overclock. I am not sure that it's going to be that much since they will probably generate a good amount of heat. I have read somewhere that you need 1 rad per apparatus you want to cool but in these days, double GPU cards did not exist as far as I know. Good luck with your build.
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#3
Will the ASUS Z87-WS work well or is there something better under $375ish for the mobo. As for cooling i guess I will just keep it air cooled and get some extra fans. As for the 7990's 4 will be fine since I will most likely build out and build a VCL ( I watched epixoip video on YouTube about it). Speaking of VCL's will these parts work with just a couple of nodes (like 2-4) CPU= Amd FX-6300 GPU= power color 7870 RAM= 8gb Adata 1600mhz Mobo= biostar A780L3C and a 500gb drive? Thank you for the help I truly needed it. Thanx And one last thing can you do a VCL infinaband setup but with fiber optic parts?
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#4
Fiber optics have same latency as copper so you will have no advantage over it.
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#5
do you have any recommendations for cheap node builds >$700 or should I jus tbuild one big setup? read the wiki ant at least 12gb ram don't care about cpu and for the gpu I was thinking one of these choices the R9 270x or 7870. thanx for the fast responses
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#6
So you need first to clarify yourself what you talking about. Node is computing machine with low spec's except GPU. Broker need to be normal to high-end CPU+RAM. If to make VCL cluster for node's I personally would go with small motherboards each 1-2 AMD cards. It's not cost efficient, but it's very easy to manage and also you will save money on things like PSU. Anyway, you will need infiniband, if you will not go with it, forget VCL.

Small mb I talking about as example:
http://www.newegg.com/Product/Product.as...6813131697
http://www.newegg.com/Product/Product.as...6813157228

Second one have no PCI, so no infiniband, but posted it just for reference. I have done something similar with 2 cards on motherboard like on first link and it still working like a clock.

p.s. interesting, is there anywhere posted latency of connections like FireWire?
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#7
i don't know about firewire but if it was faster than infiniban than im sure that epixoip would have coverd it in his videos. Also newegg does not have them and are discontinued but i found it on amazon for 150 no cpu combo. On the broker node can I use 3-4 7990? the wiki says that I don't NEED to also if you cant if i just make it one of the node (do all nodes need to be identical?)
p.s when getting infiniban cards do i need 2 ports or just 1??
pps will this work better http://www.amazon.com/M5A99FX-PRO-R2-0-9...otherboard
and how about this combo (i will use a rack mount 4u case)http://www.newegg.com/Product/ComboBundl...bo.1460245
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#8
Any ideas??
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#9
Don't do VCL, as you struggling with much more easy things. Do 2 to 4 cards setup on motherboard like:
UD7
Put CPU like FX6300, FX8350 on it, add 16 to 32 GB ram, add 1 to 2 SSD for OS and dictionary processing and you will be fine. If talking about HD7990, go with one or two for a start, as you will see how difficult to cool dual GPU cards is, also you will be surprised how much you will need to spend on PSU's ... as you will need 1200W for 2 dual card setup.
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#10
I want to water cool all 4 and how much psu will I need for that? Also expecting ddr4 in late December and new haswell cpu's ( this setup in not just for hashcat so i need other things) should i get a cheap 1150 board and wait to get a more expensive one and reuse my 1150 cpu? or even like a 2 computer vcl?
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