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Title: What hash rate can I expect from 3 x 7850s? Post by: btcminer021 on April 10, 2013, 07:27:14 PM Putting together a new rig. Using the below. Can anyone guess the expected wattage usage and hash rate?
GPU: 3 x SAPPHIRE 100355-1GOCL Radeon HD 7850 1GB 256-bit GDDR5 PCI Express 3.0 x16 HDCP Ready CrossFireX Support Video Card OC Version PSU: 1 x Corsair Professional Series HX 850 Watt ATX/EPS Modular 80 PLUS Gold (HX850) MB: 1 x ASRock MB-970EX4 Socket AM3+/ AMD 970/ AMD Quad CrossFireX& nVidia SLI/ SATA3&USB3.0/ A&GbE/ ATX Motherboard CPU: 1 x AMD FX-4100 Zambezi 3.6GHz (3.8GHz Turbo) Socket AM3+ 95W Quad-Core Desktop Processor FD4100WMGUSBX RAM: 1 x Corsair Vengeance 8 GB ( 2 x 4 GB ) DDR3 1600 MHz (PC3 12800) 240-Pin DDR3 Memory Kit for Core i3, i5, i7 and Platforms SDRAM CMZ8GX3M2A1600C9 Case: 1 x LIAN LI PC-7HB Black Aluminum ATX Mid Tower Computer Case CPU Cooler: 1 x COOLER MASTER Hyper 212 Plus RR-B10-212P-G1 "Heatpipe Direct Contact" Long Life Sleeve 120mm CPU Cooler Compatible with Intel 1366/1155/775 and AMD FM1/FM2/AM3+ I've already done the math and it looks like 1300MH/s? Max power usage would be about 750W. Anyone see any issues with these numbers? Title: Re: What hash rate can I expect from 3 x 7850s? Post by: DrG on April 10, 2013, 08:01:19 PM Which coin are you going to mine (it affects the wattage use)?
Title: Re: What hash rate can I expect from 3 x 7850s? Post by: btcminer021 on April 10, 2013, 08:30:59 PM BTC for about a month then probably LTC and converting them to BTC to cash out
Title: Re: What hash rate can I expect from 3 x 7850s? Post by: Gator-hex on April 11, 2013, 10:27:23 PM You won't get 1300MH/s unless you run 4 cards.
You can get 900MH/s easy, 1000MH/s if you push it more and don't mind it crashing now and again. Only 1xPCI-E each, 100-120w per card, 750w is more than enough. Title: Re: What hash rate can I expect from 3 x 7850s? Post by: mrSprinkles on April 11, 2013, 10:46:37 PM I'm getting around 350-360 KH/s on my 7850 mining LTC.
Title: Re: What hash rate can I expect from 3 x 7850s? Post by: DrG on April 11, 2013, 11:55:59 PM BTC for about a month then probably LTC and converting them to BTC to cash out Right now BTC mining is on par with LTC as far as income. If LTC difficulty keeps going up there would be no point converting, just stick mining BTC. Title: Re: What hash rate can I expect from 3 x 7850s? Post by: btcminer021 on April 12, 2013, 12:22:20 AM https://en.bitcoin.it/wiki/Mining_hardware_comparison
From what I can tell from the table and others' experience, 300-400MH/s per card would be doable, no? I guess time will tell! Title: Re: What hash rate can I expect from 3 x 7850s? Post by: Gator-hex on April 12, 2013, 12:36:26 AM You wont see 400MH/s unless you run 7870s
I think sometimes people quote unstable MH/s on that page that only last a few minutes. Anything over 330MH/s will crash a lot. Title: Re: What hash rate can I expect from 3 x 7850s? Post by: DrG on April 12, 2013, 12:44:32 AM On that mining hardware page what you find is a lot of extremes. Like the person only getting 525MH/s with a 7950. Or somebody mining with a 7970 outside in a snowy area so that they are able to overvolt the card to crazy voltages and fan speeds.
Any time you run multiple cards the weakest card will bring the rest down even if you use independent settings. The heat from each card increases the power usage by requiring more fan speed and voltage to remain stable. Expect 310 from each card, and anything above that is good luck and some skill with tweaking. Title: Re: What hash rate can I expect from 3 x 7850s? Post by: chaosgs on April 12, 2013, 06:59:26 AM Running 2 rigs (soon to be 4 rigs) with 4 7850s each.
Each GPU gets 320 M/hash at 1095 OC. For a 24/7 operation I cant get them to go higher. Also its open air non cased, in front of a window AC unit..... 7850's are the best bang for buck, unless you can get 7950's on sale. Title: Re: What hash rate can I expect from 3 x 7850s? Post by: chaosgs on April 12, 2013, 07:01:16 AM Oh I forgot the best part. Im pulling 580 watts out of the wall with those 4 gpus. I bought a watt meter to keep tabs on my power. Doing math X3 would prob consume 450 watts.
Title: Re: What hash rate can I expect from 3 x 7850s? Post by: btcminer021 on April 16, 2013, 04:46:39 PM Spot on! 3x GPUs is about 460 Watts! :)
I was getting about 750MH/s with 3x GPUs, but the middle one was running too hot. Now with 2xGPUs I get 525MH/s, so about 250MH/s each. This is stock. I will start OC tonight. I'm hoping for at least 300MH/s each OC. Next step is to get risers so I can get some more airflow between the cards. Suggestions to support the cards without PCI brackets? Title: Re: What hash rate can I expect from 3 x 7850s? Post by: btcminer021 on April 17, 2013, 09:05:49 PM FYI I've got only two running right now due to high temps with the middle card. Need to see how this is going to work in a closed case with three cards. May have to seriously change the plan.
With 2 x 7850, both OC to 1200MHz Core, 1300MHz Memory @ 1.18V, fan speed 85%, about 330Mh/s with cgminer intensity 9, and about 73-75C each under load for a day. I'm petty happy with this, but certainly hoped for more! I could play more but am OK for now until I get a few BTC. Any suggestions? Would changing the intensity help at all? Title: Re: What hash rate can I expect from 3 x 7850s? Post by: Extornia on April 17, 2013, 10:58:12 PM Your clocks are bad and you should feel bad. Experiment. My perfect ratio is 912core and 1250 mem, (this is a 5770 and a 6770) I get 210kh/s. If I put it to 913core i drop to 160kh/s and 1250+ mem drops aswell. Also this is about scrypt. There is no point doing bitcoin with only those type of GPU's. Do litecoin.
To cool your gpu's get 2 fans, pushing air inbetween the gpus. Title: Re: What hash rate can I expect from 3 x 7850s? Post by: Operatr on April 18, 2013, 12:44:39 AM Well this is handy info, I am typing this post from my new mining rig ;D 3x 7850's also.
These are Sapphire HD 7850 OC's, they have an open air style dual-fan heatsink, we'll see how they handle the heat after some OCing. These things can be had for about $165 all over the place, seemed to be the best deal for the power they can deliver. Title: Re: What hash rate can I expect from 3 x 7850s? Post by: Operatr on April 18, 2013, 04:10:11 AM Ok, it was pretty easy to ramp these Sapphire's up to around 320 Mhash/s from 250 stock, with a core clock of 1106 and a slight voltage bump with the TriXX utility, no problems so far. I can see the middle card getting fairly warm, Ill need to throw some more fans around them to go further probably. Grand total 960 Mhash/s
Title: Re: What hash rate can I expect from 3 x 7850s? Post by: chaosgs on April 18, 2013, 11:24:42 AM I cant get my cards to stay stable at 1100 core clock, so I keep them at 1050. Sucks because they dont go over 70C, tend to stay around 60C.
Title: Re: What hash rate can I expect from 3 x 7850s? Post by: killerbread on April 18, 2013, 03:38:15 PM Why do you need a case? You're going to trap a lot of hot air inside.
Title: Re: What hash rate can I expect from 3 x 7850s? Post by: btcminer021 on April 18, 2013, 04:11:51 PM Can you guys post you OC settings like core and men clocks, voltage, fan speeds,etc? I've hit a limit and my middle card is over 100C!
Title: Re: What hash rate can I expect from 3 x 7850s? Post by: shockr on April 19, 2013, 05:22:36 AM Ive been mining litecoin so im not too sure how the numbers compare.
I have 3x 7850 @ 1100 Core/1200 Memory, average around 380KH/s each ./cgminer --lookup-gap 2 -I 20 --thread-concurrency 8192 -w 256 https://i.imgur.com/oD2ovzF.png Title: Re: What hash rate can I expect from 3 x 7850s? Post by: Operatr on April 20, 2013, 04:08:00 AM Ive been mining litecoin so im not too sure how the numbers compare. I have 3x 7850 @ 1100 Core/1200 Memory, average around 380KH/s each ./cgminer --lookup-gap 2 -I 20 --thread-concurrency 8192 -w 256 https://i.imgur.com/oD2ovzF.png Thanks for the specs, I in cgminer Im rolling around 320 Khash/s each with similar settings, I will try this config and see if it improves. Title: Re: What hash rate can I expect from 3 x 7850s? Post by: Operatr on April 21, 2013, 11:54:28 AM With 1100 clock/1250 mem 1.46 vcore and --intensity 14 --lookup-gap 2 --thread-concurrency 8192 --worksize 256 -g 1 I am able to pull in around 370 KHash/s mining Litecoin without any stability issues or cgminer errors, averaging 955 KHash/s with 3 cards.
Title: Re: What hash rate can I expect from 3 x 7850s? Post by: ryantc on April 25, 2013, 02:27:42 PM Running 2 rigs (soon to be 4 rigs) with 4 7850s each. Each GPU gets 320 M/hash at 1095 OC. For a 24/7 operation I cant get them to go higher. Also its open air non cased, in front of a window AC unit..... 7850's are the best bang for buck, unless you can get 7950's on sale. what's the PSU your are using to power up these 4 together. BTW which 7850 still have undervolt feature available or are they all locked now? Title: Re: What hash rate can I expect from 3 x 7850s? Post by: ewitte on April 25, 2013, 03:17:35 PM Bitcoin - I can get about 330MH/s off the 7850 vs 430-450MH/s on the 7970's
LTC - I can get close to 400KH/s on the 7850 The 7870's have some kind of issue I haven't resolved yet but so far they are mostly BTC. I've seen 550-750KH/s (depends on intensity) off the pair but the actual work completed (U: score) is closer to 350KH/s. Title: Re: What hash rate can I expect from 3 x 7850s? Post by: btcminer021 on April 26, 2013, 08:22:10 PM For the record, running stable at 341.9Mh/s. Still experimenting.
Title: Re: What hash rate can I expect from 3 x 7850s? Post by: fnord123 on April 28, 2013, 10:53:25 PM FWIW my ASUS HD7850-DC2-2GD5-V2 is giving 331Mh/s. This is with 1100 engine, 950 memory, intensity 7, diablo kernel under CGminer 3.1. Temp is running 60C.
Title: Re: What hash rate can I expect from 3 x 7850s? Post by: Operatr on April 29, 2013, 04:21:28 AM I'm able to get around 360 kHash per card with moderate OC in Scrypt mining with my 7850s, could probably get that up more with some better cooling.
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