But you would also need to find a board that recognizes and can actually use all the cards. You might need to edit the BIOS for that and good luck with that. And then there's another possible limitation on the OS level. And then the driver, the miner and your overclocking tool if you want to OC would also all has to be able to use so many cards.
And you would also need more RAM and a better CPU than you'd need for a 6 card rig and then you would have to use multiple PSUs which can also be tricky and so on.
I think it's too much work for too little possible benefit.
Topic: Adding more than 6 GPUS to a rig (Read 1927 times)
if you are building a big farm i could see this being a good thing, because every 4 rig you save one, 8 x 3 vs 6 x 4, if the splitter cost very low you can save up to $400 or more because of the psu also
apparently yes you can do it https://hashcat.net/forum/thread-2622.html
That could be too expensive. I have 8 GPU in most rigs. That is the combination of 2x7990+4x7970 or 4X390.
is 390 hashing well compared to 290 ??
390 is the same as the 290, but a little bit more efficient. The memory speed is higher, 1500 instead of 1250.
Windows will only recognize 8 GPU's. Linux might recognize more, but at that number of GPU's other issues start popping up, you may have to tune each board, as some boards do not like the clock settings that other boards will be ok with.
Stick to 6 GPU's its easier.
Stick to 6 GPU's its easier.
apparently yes you can do it https://hashcat.net/forum/thread-2622.html
That could be too expensive. I have 8 GPU in most rigs. That is the combination of 2x7990+4x7970 or 4X390.
is 390 hashing well compared to 290 ??
apparently yes you can do it https://hashcat.net/forum/thread-2622.html
That could be too expensive. I have 8 GPU in most rigs. That is the combination of 2x7990+4x7970 or 4X390.
The 7990 is technically a dualgpu but on one PCB so technically he still has 6 physically separate GPUs. But in the OS it's 8 GPUs.
That is right right. 2X7990 = 4X7970. But it is more efficient than the ordinary 7970 as the ASIC quality is higher.
apparently yes you can do it https://hashcat.net/forum/thread-2622.html
That could be too expensive. I have 8 GPU in most rigs. That is the combination of 2x7990+4x7970 or 4X390.
The 7990 is technically a dualgpu but on one PCB so technically he still has 6 physically separate GPUs. But in the OS it's 8 GPUs.
apparently yes you can do it https://hashcat.net/forum/thread-2622.html
That could be too expensive. I have 8 GPU in most rigs. That is the combination of 2x7990+4x7970 or 4X390.
If the AMD supports 8 to 16 GPUs in one rig with splitters, then it might be good to buy it and use it.
Im not so sure...
I dont know what the max the software/drivers can support is but if we go just on pcie slots, you can get a 6 slot board and put a 3-way splitter in each giving you 18 GPUs on a motherboard. That thread said splitters were less than $200 each. $200 x 6 is $1200 just in splitters to run 18 GPUs. You can get 5 slot boards with CPU and RAM for about the same cost. So 6 boards will give you 30 GPUs for about the same price.
If the AMD supports 8 to 16 GPUs in one rig with splitters, then it might be good to buy it and use it.
apparently yes you can do it https://hashcat.net/forum/thread-2622.html
That could be too expensive. I have 8 GPU in most rigs. That is the combination of 2x7990+4x7970 or 4X390.
yeah those splitter are too expensive, it's better to buy a new rig, which in the end should be cheaper but not by much, it depend on the power you need
Thanks. Thats what i was wondering. I think i will just build a 3rd rig and call it good. It will cost only about 400 more to finish the 6 GPU rig out to a full build vs a whole bunch of parts that would be useless when mining has slowed to no profit. (hopefuly never) 
After two weeks i finally have my two rigs up and running. Should receive my first payout some time today from ethpool. I have two H81 pro boards and 6 sapphire r9 280x with Lepa 1600w power on each. I was thinking of adding two more cards to each rig. Can I purchase this http://www.newegg.com/Product/Product.aspx?Item=9SIAAK94494220 and still be ok with just 1600w supply or should i not do it. I dont have a power meter to test the current wattage. AMD states 225w but idk what they are currently pulling. Its all stock and no overclocking. I would like to also see if someone has a modded bios for this card. I remember reading somewhere that they had the wattage down to around 145w and still pulling over 20mh. That would be awesome if anyone has this. 
Running Windows 10 pro one with 4gb and one 8gb memory.
Running Windows 10 pro one with 4gb and one 8gb memory.
5-6 GPU , that should be your max lol. don't go for "e-peen" when mining "e-golds". Not sure if your cost savings will net out compared to reliability.
apparently yes you can do it https://hashcat.net/forum/thread-2622.html
That could be too expensive. I have 8 GPU in most rigs. That is the combination of 2x7990+4x7970 or 4X390.
apparently yes you can do it https://hashcat.net/forum/thread-2622.html
After two weeks i finally have my two rigs up and running. Should receive my first payout some time today from ethpool. I have two H81 pro boards and 6 sapphire r9 280x with Lepa 1600w power on each. I was thinking of adding two more cards to each rig. Can I purchase this http://www.newegg.com/Product/Product.aspx?Item=9SIAAK94494220 and still be ok with just 1600w supply or should i not do it. I dont have a power meter to test the current wattage. AMD states 225w but idk what they are currently pulling. Its all stock and no overclocking. I would like to also see if someone has a modded bios for this card. I remember reading somewhere that they had the wattage down to around 145w and still pulling over 20mh. That would be awesome if anyone has this.
Running Windows 10 pro one with 4gb and one 8gb memory.
Running Windows 10 pro one with 4gb and one 8gb memory.
Jump to: