Author

Topic: Shocking! another is my rig good enough? (Read 1642 times)

newbie
Activity: 13
Merit: 0
June 10, 2011, 11:24:47 AM
#16
get slot extenders from cablesareus.com
cablesareus.com.au ?
woo
newbie
Activity: 10
Merit: 0
I heard people saying you need 1 cpu core per GPU to maximize the GPU power. Can anyone confirm this? if that was true, then you'll need a quad core CPU for 4 x GPU, and 6 core CPU for 5 x GPU
Definitely not true.
legendary
Activity: 1806
Merit: 1003
I heard people saying you need 1 cpu core per GPU to maximize the GPU power. Can anyone confirm this? if that was true, then you'll need a quad core CPU for 4 x GPU, and 6 core CPU for 5 x GPU
full member
Activity: 154
Merit: 100
Yeah I'd also recommend going with a cheaper motherboard and smaller PSU and doing 2x systems w/ 2-3 cards each.
newbie
Activity: 8
Merit: 0
Going to try and avoid the case thing and let it sit in a corner of our Server Room
sr. member
Activity: 392
Merit: 250
Thanks for bringing that up -- there are so many reasons 2 per case is good, I forgot a few Smiley

Heat dissipation is a real big one. I didn't appreciate how big of a deal it was until I got 2 cards in one machine. Both cards are hotter than they would be separately.  Imagine 3 or 4 sitting together in one case! More heat means less stability, more noise, and less overclocking ability.

Remember, the CPU doesn't draw much power unless it's being run at 100%. I would advise against CPU mining -- not worth it.
So having 2 CPUs in two machines to power 4 cards, vs. 1 CPU in one machine, is almost negligible.
newbie
Activity: 33
Merit: 0
The usual, been lurking for awhile, got paid and time to move on from the Nvidia 570 and 9800 I have been using.  This will be a dedicated mining rig, power not an issue, cooling shouldnt be as well (in a room with other servers).

MSI 890 Motherboard w/ the 5x PCI E
2x  SAPPHIRE 100311SR Radeon HD 6970 2GB (http://www.neweggbusiness.com/Product/Product.aspx?Item=N82E16814102915)
Antec 1200 Watt PSU
2gb crappy ram
shitty cheap HDD
Sempron 140

The 6950 Reference card I wanted is now out of stock at newegg unfortunately and was going to get 4 or 5 of those.  In the meantime until they get restocked I figured I'd start w/ the 2x 6970's and add in 3x of the 6950's later (would be flashed).

1) If I've been reading correctly the 6970's have 2x gpu cores each on them, or is that just the 6990's?
2) Should I move to 1500watt PSU in anticipation of additional 3 cards and to have some extra headroom?

Thanks guys, I love the community here so far

1) Only 1 GPU core, that's just the 6990s.

2) Only if you plan on running linux. Windows has a limit of 4 GPUs per system. To use 5 means you need linux. You may also want to consider the issue of heat. 5 cards in a case will generate a HELL of a lot of heat, and they'll be crammed pretty close together. You really don't want that.
newbie
Activity: 8
Merit: 0
Matt - You make some wonderful points and will modify from there.  While I have seen these threads over and over for the last week I appreciate very much what you have said.  We all just want to make sure our first mining rig will be right. Smiley
sr. member
Activity: 392
Merit: 250
In my opinion, it's better to stick to 2 cards per PC.
When you try to cram 3 or 4 cards in a PC -- you're not saving that much, really!

1000W power supplies are more expensive than 750W, which are more expensive than 500W. There's not even much of a "quantity discount" -- each card costs about $50 to power (assuming you're not going bottom-basement on the quality of your PSU)
And even if you go bottom basement -- you're talking $30 for one, $60 for two, or $100 for three. So it still holds.

Even if you were paying slightly more for 2 PCs, think about DIVERSIFICATION. With one tower, if that PSU goes south (OR your RAM, OR your hard drive, etc.) you're going to be getting 0 MH/s for a while. With 2 PCs, you'd at least get 50% of your usual MH rate.
One tower with 5 cards is "putting all your eggs in one basket" if I ever saw it!

And which would be easier to resell? Which one has more potential customers on Craigslist? Obviously the 2 "regular" PCs. More potential customers = more demand, which means you can get a higher price. So another +1 for my strategy.

You won't run into "Windows can only handle 3 GPU" issues if you stick to 2 cards per machine. Even just ONE card in a "micro ATX" single-PCI-E motherboard is not cost-prohibitive. You can get away with a smaller power supply, etc. I'm not advocating ONE per machine, but I wouldn't rule it out as being "not worth it" or something.

Motherboards with 3 or more PCI-Express slots are probably more expensive/rare than ones with 2 slots. That is true whether your source is online, ebay, or craigslist. There are simply MORE mobos out there with 2 slots.

And power consumption isn't much less (if it's less AT ALL) when you have 4 cards crammed into a full tower case with extender cables vs. having 2 PCs with 2 cards each.

I think it's less hassle and doesn't cost you any more (money OR power consumption) to have 2 cards per PC.

The cards are your real limiting factor. There are other factors as well (how much you can fit on one electric circuit at your house) It's easy to find a used barebones PC or build one.

Feel free to donate if you appreciate my advice Smiley

Matthew
member
Activity: 70
Merit: 10
I don't think there's a single MOBO that can fit 5 high-end cards to it. The cards take two slots each.

Other than that, I Think your plan is good to go. Just keep the mobo laying flat on a surface; as heat rises upwards it becomes impossible to use a normal tower case with 3++ cards.

you will definitely want slot extenders for 5 cards and you will want to build a rack to mount them with some airflow space between them.

get slot extenders from cablesareus.com

and check out the different ways people mount cards here: http://forum.bitcoin.org/index.php?topic=7216.0
newbie
Activity: 2
Merit: 0
1) Just the 6990s.
2) 6970=250W,  6950=200W (both absolute maxima though), so 2x6970+3x6950 gives you a total of 1100W only for the GPUs. I would rather play it safe and buy the bigger PSU, if you are sure about upgrading. You don't want it to die.
newbie
Activity: 14
Merit: 0
Psu is good even for 3 more cards but might burn out. i dont know its rating. with the mobo your using you can only fit 4cards unless you plan on using extenders
i believe it only has 1 core the 6990 has 2 and the 5970( i think it is)
everything else is good go with a SSD not a HDD. get a USB and use linuxcoin cheaper&less power
full member
Activity: 216
Merit: 100
I don't think there's a single MOBO that can fit 5 high-end cards to it. The cards take two slots each.

Other than that, I Think your plan is good to go. Just keep the mobo laying flat on a surface; as heat rises upwards it becomes impossible to use a normal tower case with 3++ cards.
member
Activity: 70
Merit: 10
the 6970's have only one GPU but still really good hashrates.  your rig looks good to me Smiley  but i am a noob so my opinion probably isnt worth the 0.04 Smiley

and i would definitely start with the 1500w psu if you plan to add 3 more 6950s
newbie
Activity: 8
Merit: 0
Not even a pity reply of looks good?  .04 BTC to the person who confirms for me. Thanks
newbie
Activity: 8
Merit: 0
The usual, been lurking for awhile, got paid and time to move on from the Nvidia 570 and 9800 I have been using.  This will be a dedicated mining rig, power not an issue, cooling shouldnt be as well (in a room with other servers).

MSI 890 Motherboard w/ the 5x PCI E
2x  SAPPHIRE 100311SR Radeon HD 6970 2GB (http://www.neweggbusiness.com/Product/Product.aspx?Item=N82E16814102915)
Antec 1200 Watt PSU
2gb crappy ram
shitty cheap HDD
Sempron 140

The 6950 Reference card I wanted is now out of stock at newegg unfortunately and was going to get 4 or 5 of those.  In the meantime until they get restocked I figured I'd start w/ the 2x 6970's and add in 3x of the 6950's later (would be flashed).

1) If I've been reading correctly the 6970's have 2x gpu cores each on them, or is that just the 6990's?
2) Should I move to 1500watt PSU in anticipation of additional 3 cards and to have some extra headroom?

Thanks guys, I love the community here so far
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