New 6990 Setup Questions

[Acejam]

Hey all,

I managed to find a source who has some Gigabyte 6990's in stock. I was originally looking for XFX or Saphire, but I've read great things about Gigabyte as well and the opportunity presented itself. Right now I'm running:

i7 920 @ 4Ghz (air)
12 GB Corsair Dominator
80GB Intel X25-M SSD
(4) 2TB Samsung HD204UI in RAID10
BFGTech GTX285
Corsair 750W Power Supply
Antec 1200
CoolerMaster V8


I'm thinking about ditching the GTX285. With a slight overclock, my current hash rate is around ~60 Mhash/s. I'd like to jump into mining head first, and I'm considering this an "investment opporunity". Not to mention, I play Starcraft 2/COD, and I'm just a geek in general.

Questions I have:

1. Will I need a bigger PSU? For 1 card I think I'd be OK, but for 2 6990's I think I'm going to need at least 1000W+. If I were to get one of these (probably a Corsair one), do they require any special power rails for my household wall power jack?

2. Any issues with Gigabyte cards that I didn't find? For the most part all of the cards seems to be the same GPU core and such, just different plastic casings, fans, and warranties. Gigabyte has ~3 years IIRC. (yes I know XFX double lifetime, blah blah)

Please feel free to critique.  

Thanks,
Josh

[1502897022]

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[1502897022]

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[Strongbow]

Q1. 750w will definitely be enough for 1 6990, and will definitely not be enough for 2. I would say 950 at least if you're running 2 6990's.
Q2. Nah, gigabyte brand will be fine, go for it

Side note: i would say don't go with 2 6990's, better purchases can be made for pretty much any use you have.

[Acejam]

Thanks for the input guys. Unfortunately I've learned that this online seller is sketchy and therefore my deal fell through. I don't want to risk my money on that shop.

Anyone know where I can buy some 6990's? I'm looking for 2. 

[mattpker]

As previously said by another user, I would not buy 6990's. A better price per performance are 6950's that are unlocked to 6970's.

The following card can be unlocked:

http://www.newegg.com/Product/Product.aspx?Item=N82E16814127555&cm_re=6950-_-14-127-555-_-Product

You can unlock it by following these directions:

http://www.techpowerup.com/articles/overclocking/vidcard/159


These can do 400Mhash/s per card for $270. 6990 can do 800Mhash/s per card for $750+. As you can see, building multiple machines with 6950's is a much smarter option.

[Acejam]

I'd set yourself to autonotify on Newegg.  The should be getting a shipment within a day or so (Tuesdays, in my experience).  Just be sure to jump on it - last week when they got an order of reference 6950s, I was barely able to get one (sold out in about 5 hours).

Good point. I've already done this for the XFX, HIS, and Gigabyte models on there. I even turned "PUSH" on my iPhone on so I'll get the email ASAP. I talked to someone on live chat from NewEgg and they said the order was expected in 1-2 weeks when it was ordered just over a week ago - so any day now.

As previously said by another user, I would not buy 6990's. A better price per performance are 6950's that are unlocked to 6970's.

The following card can be unlocked:

http://www.newegg.com/Product/Product.aspx?Item=N82E16814127555&cm_re=6950-_-14-127-555-_-Product

You can unlock it by following these directions:

http://www.techpowerup.com/articles/overclocking/vidcard/159


These can do 400Mhash/s per card for $270. 6990 can do 800Mhash/s per card for $750+. As you can see, building multiple machines with 6950's is a much smarter option.

Another good point. Though I only plan on running 1 machine - my main desktop - therefore I'd like to cram as much power into that single box as possible. I don't mind spending the money if I can get the associated GPU processing power with it. Hopefully each 6990 will be able to turn ~800Mhash/s each.

[Strongbow]

If you intend to run two 6990s, my understanding is that you'll need to run Linux.

Nope. Windows can do 4 GPUs, 2 in each of the 6990's. It would work fine.

[padrino]

Another option for those looking for a good deal, the XFX HD-695X-ZNFC can be had for $209 after rebate and a number of people also unlocked them, not reference cards and 1GB of RAM but for BTC it may be a great option.

[xen82]

I had a 650WCorsair PSU and could only run the card on 830MHz (but then again my CPU is a i7-2600. I recommend getting a stronger PSU if you want to run two cards, I got a Thermaltake 1200W for my system running 2 cards @ 880MHz.

On a side note, when people get 800MHash/s on the 6990, how do they go about that?
I average about 310-320MHash/s per 880MHz GPU core (running Ubuntu 10.04 x64, Catalyst 11.5, 2.4 drivers, and Phoenix 1.48). On my Windows 7 x64 box I get 343 MHash/sec on Phoenix 1.48 and the latest drivers/SDK. Suggestions?

[accod]

Try running a single core on the 6990 and see if you get closer to 400MHash/s.  Also check to see if your core speeds stay at 880MHz or are jumping about a bit.  I found the power throttling kicked in on mine and needs to be raised before you can get 400MH/s on both cores at the same time.

[mjhorn]

Try running a single core on the 6990 and see if you get closer to 400MHash/s.  Also check to see if your core speeds stay at 880MHz or are jumping about a bit.  I found the power throttling kicked in on mine and needs to be raised before you can get 400MH/s on both cores at the same time.

Are you running Windows or linux with on your setup? I'm looking for more info on the power throttling under linux, but so far have only found anything useful for Windows.

[itsagas]

750W for two 6990 is not enough.  I have two 6990 running and they are using 880W while mining under full load (with a 1000W PSU).  Also, they throw off tons of heat and suck more power than my 4x9650 setup.  The 4x9650 draw under 800W under full mining load, run cooler and get a better hash rate than my 2x6990.  And the 6950s were way cheaper to buy. 

Hope it helps. 

[accod]

Try running a single core on the 6990 and see if you get closer to 400MHash/s.  Also check to see if your core speeds stay at 880MHz or are jumping about a bit.  I found the power throttling kicked in on mine and needs to be raised before you can get 400MH/s on both cores at the same time.

Are you running Windows or linux with on your setup? I'm looking for more info on the power throttling under linux, but so far have only found anything useful for Windows.

Windows for now until I decide on the volts, clock, and fan speed I want to run and then I'll modify the bios and run linux.  Afaik if you switch to the second bios it will disable power throttling but I'm running on a 520W PSU so don't want to risk this (my rig uses 360W at 300MH/s x2 (750MHz iirc)).

[Acejam]

Lots of good info/suggestions in here - thanks guys!

Yeah for 2 cards my 750W PSU isn't enough. I think I've found 2 PowerColor 6990's for sale that are lightly used, so I'm going to try and pick those up, along with a 1200 watt Corsair PSU. Is 1200 *too* much? I want to perhaps add a 3rd card in the future... (but I'd need to run Linux for that, when the time comes)

[AmpEater]

Lots of good info/suggestions in here - thanks guys!

Yeah for 2 cards my 750W PSU isn't enough. I think I've found 2 PowerColor 6990's for sale that are lightly used, so I'm going to try and pick those up, along with a 1200 watt Corsair PSU. Is 1200 *too* much? I want to perhaps add a 3rd card in the future... (but I'd need to run Linux for that, when the time comes)

1200 corsair PSU is great.  No such thing as too much capacity.  That will allow you to run 3 cards in the future

[Jack of Diamonds]

Please feel free to critique.  

Thanks,
Josh

IMO 5850's are the best reference card, costing slightly over $100 dollars and yielding from 280 to 330 mhash/s.
In comparison a $500-$600 dual GPU card fetching merely ~650-700mhash/s at stock speeds seems like a bad hardware investment.

The only problem is availability, you would be hard pressed to find many in new or mint condition. However there are plenty of used ones on the open market.

[AmpEater]

Please feel free to critique.  

Thanks,
Josh

IMO 5850's are the best reference card, costing slightly over $100 dollars and yielding from 280 to 330 mhash/s.
In comparison a $500-$600 dual GPU card fetching merely ~650-700mhash/s at stock speeds seems like a bad hardware investment.

The only problem is availability, you would be hard pressed to find many in new or mint condition. However there are plenty of used ones on the open market.

This comparison is meaningless without Mobo/Ram/CPU/PSU/Case/HD costs factored in.  In my case (dual 5970 rigs) GPUs make up 65% of the cost of a mining rig.  For 5850s hardware costs will be over 50%

[Acejam]

I have (2) Diamond HD6990's on the way...should be here tomorrow.

Just picked up a Corsair Pro 1200W PSU @ MicroCenter, they price-matched NewEgg for me.

Putting the cards in tomorrow - will I need a VGA dummy plug? Or should I crossfire the cards? (Quad-fire rather) I'll be running in Windows 7 x64 Ultimate for now using GUIMiner. Should I run a command line client instead?

[Acejam]

Cards should be arriving later today.

Installing this as well later tonight:

[EPiSKiNG]

Cards should be arriving later today.

Installing this as well later tonight:

Windows can be wierd about crossfire.  I have a 6990 and 2 5870 but no crossfire enabled, then I have another box with 2 5970 that requires the crossfire cable to be installed in order for opencl to recognize all 4 cores.  It used to be (stream 2.1) that crossfire degraded performance, but I've seen that with sdk 2.4 that problem has been fixed.

EP

[Acejam]

Installed both cards and the AX1200 tonight - however I'm facing a new issue. I was able to install ATI Catalyst software w/ the latest drivers and SDK 2.4.

However, the system won't get past the "Starting windows" screen during Windows 7 x64 bootup, with both cards plugged in. If I unplug both PCI-E power connectors from one of the cards (doesn't matter which one), then system will boot up fine and will *not* hang at the "starting windows" screen. I'm not CrossFire'd or anything like that yet, just 2 indivudal cards. Do I need a VGA dummy plug or something? Eventually I'd like to CrossFire, but regardless if the GPU is being used or not, I'd like to be able to boot into Windows with both cards powered on and plugged in.

The PSU is 1200 watts. Could extra HDD's be the issue? I have the following:

(1) 80GB X25-M Intel SSD
(4) Samsung HD204UI 2TB HDDs in ICH10R RAID10

5 HDD's
(2) Diamond 6990's
i7 920 (4.0ghz on Air, stock for now just for testing)
Asus P6T (vanilla)
CoolerMaster V8
12GB Corsair Dominator 1600
1200Watt Corsair PSU (AX1200)

Thoughts?