Bitcoin Forum

If you have, what hashes are you getting? :D

I ordered 2 yesterday, 7870 crossfire, well see what happens :)

That should be awesome :D

http://www.tomshardware.com/reviews/radeon-hd-7870-review-benchmark,3148-18.html

They look ok I suppose. They won't replace the HD 5830 while there are some still on the market. Curious what the power consumption will be while mining at 1.2 GHz on the core and 300-500 MHz on the ram.

Those benchmarks are worthless, Tom's doesn't know how to bitcoin mine.  For example, the 7970 which can do 600mhash with diablominer was doing 330~ on the tom's hardware benchmark.  It's that bad.

Based on simple extrapolation I'd bet the 7850 could do 400+ mhash, and 7870 450+ mhash... but this is just a semi-educated guess based on actual performance numbers for the 7970 vs tom's terrible benchmark result.

I have a feeling 7970 will reign top tog until the dual GPU card comes out.  For the 7 series at least.

Calculated hash rate for 7850 is 255mhs on stock clocks.
7870 = 370mhs and both cards worthless as investment like a 79xx series.
I think real hashrate will be identical to calculated values.

The only perk the 7 series has with it is power usage.  Other than that, Mh/$ is still 5xxx series.  But 7 series are nice to have as future proof. nice warranties too.

For MH/w, it's gonna be better than 5830 and the 68xx series.

Any update?

xtech, did you get yours in and setup?

I have two 7850s coming in today replacing two 6870s. I'll try and report back tomorrow on their performance.

ifl

I am curious with the 78xx series as well. If anyone has them, please report everything about it.

My 2 7850s are setup but testing has been fairly limited. I can only adjust the core clock with the ATI drivers. The newest Afterburner (beta 15) locks up by system right away and I haven't had the time to try out any other versions.

Hopefully I can find a working version so that I can try knocking the memory and voltage down a bit but right now I have both cards clocked up to 1050 core (stock 860 on one 975 on the other) with stock memory (1200) and stock voltage (1.138). I'm getting 300Mh out of each with a total system wattage of 293. 110 of that is the system itself so Mh/W right now for the cards alone is 3.27.

That is a bold prediction.  The most powerful GPU will be the most powerful GPU.

Well fancy that... it looks like Tom's Hardware was in the ballpark on performance for the 7850. If they dropped $50 or so and could clock up to 1.2 GHz on the stock cooler AND achieve ~3-4 MH/w they might be a viable option for myself. That'd put them in HD 5850 territory with much lower power consumption and a warranty to cover another year or so of GPU mining.

Thanks for the results. Please update w/ new numbers if you do find a way to downclock the ram. Also, might be helpful to test with 1 GPU and then 2 GPUs so you can isolate the power consumption better. Just a thought.

Calculated mhs for 7850 @1050 for diablominer is 311mhs. 300 seems ok.

110? May be you wrong... I have i7-2600k@4.2 + P67 + 8GB +SSD +HDD and total system power on Windows IDLE is 54W from wall (80 gold+ PSU) of course WITHOUT installed videocards.

Depends on the drivers'/miners' cpu usage and the mobo and cpu themselves.

Still haven't been able to undervolt or change the memory speed but I have better power numbers now.

Currently pulling 298W and the system is actually only 71W of that not the 110W as before. I've also found that poclbm is about 5% faster than diablo for me resulting in a new speed of 314Mh each.


Sidenote: I bought 2 different brand 7850's one Gigabyte http://www.newegg.com/Product/Product.aspx?Item=N82E16814125419 (http://www.newegg.com/Product/Product.aspx?Item=N82E16814125419) and one HIS http://www.newegg.com/Product/Product.aspx?Item=N82E16814161406 (http://www.newegg.com/Product/Product.aspx?Item=N82E16814161406). The Gigabyte pulls 105W and the HIS pulls 122W. I'm assuming the Gigabyte's HSF design keeps it much cooler resulting in the fan spin much less

Not sure you're losing the power to a faster spinning fan, might be that as temperature increases, resistance increases.  Ultimately you need to push a little more current to maintain voltage.  I have no actual analytical data to support this for these circumstances, but as far as electronics theory goes...

bumping from page 2

Anything new?

I just got a Sapphire HD7850 to go into my new build and was wondering if there are any flags to go with GUI miner yet. The rest of my spec are i7 3770, 8GB memory, and a 60GB SSD for my operating system backed up with a 500GB HDD for storage. :)

Don't use GUI Miner.  Instead use CGMiner or DiabloMiner.

Intensity: 7
Vectors: 1
Work size: 256

WHta is wrong with GUI miner? I have used it for over a year and it has served me well so far. It also is giving me 308mh/s at present with my new card. With extra flags it used to give me 207mh/s on my old hd 6770 which was very good for that card, my son has that one now. Do the other miners offer better than what I presently get? This is why I was looking for extra flags to push the hash rate up. Thank you for your reply and any further info you can share. :)

better kernels

GUIMiner is just a frontend. It's not a miner. You can plug in the kernel you want (diakgcn/phatk2/opencl/etc) with the miner you want (poclbm/phoenix/etc) and have the same performance as the more popular miners. Some people just don't want all the bells and whistles and stick to what works. Why fix it if it ain't broken?