There has been a lot of discussion about unlocking the extra shaders on the 6950.  I was wondering what people have seen in the real world for a performance boost?

Wondering if it is better to
1) go with a reference card that you can unlock but might be limited in OC?
-or-
2) go with non-reference card that OC's really well (e.g. Gigabyte 6950 OC) but not unlock?

With my Gigabyte 6950OC running at 900Mhz I get about 366Mh/s now.  I am buying a dozen more GPUs and would really like to stably do 400Mh/s or better

I don't know about the power draw with 5850's, but with three 6950's and a sempron 140 i draw about 750W.  If the power draw is similar, you could do it, but as you get closer to the max output of the PSU the power might not be as clean and you lose efficiency, not to mention that it might cause too much heat/wear out the PSU over extended use. I would use at least 850W in your config unless the 5850's use a lot less power than the 6950's.

I just picked up a few A870's.  It does look a bit different from the picture.  In the picture it seemed like the two x16 slots were fairly far apart.  But since my GPUs (6950's) are double slot, they would actually be right next to each other.  So I'll have to get risers for the x16 slots too.

Still haven't had time to test it, but plan to tonight.  Eager to see if it works.  I have six 6950's now.  Even a 20 Mh/s boost on each card would really add up.

I'll give it a try tonight when I get one set up.  What I've seen is that if my GPUs have two slots of space between them then the temps are nice and low - 60C - even when overclocked.  This board has one x1 slot between the two x16 slots.  Hopefully that will be enough.  If not, I'll just get more risers.

I love Bitcoin, but if came down to it, I'll take her over BTC any day    Still, I'd like to have my cake and eat it too!

Interesting.  I get about 2 Mh/s better with the 256.  I might give it another try. 

I was planning to try a two via risers and two in the slots configuration and see what the temps are like.  If it's too high, I'll go all with risers.

Thanks for the tip on headless.  Yes, these will be headless linux rigs

Cheers

Awesome.  Just what I needed to know.

Thank you! 

Thanks!

I'm planning to go PCIe x1 to x1, which requires trimming off the back of the connector to fit on the x16 GPU connector.

Question is whether you need to short any pins for the x1 approach to work with this board?  On some other boards, such as the MSI 890FXA-GD70, it seems you have to.

I am planning to build a few Linux-based rigs with four GPUs per system (using extenders).  Before I buy, just wondering:
1) is it stable?
2) can you use extenders without shorting pins to make it work?

Thanks  

Phatk was lower on my 6950's for some reason too.

BTW, if you have 6XXX series, the work size should be 256.  You'll get a slight boost.  Use 128 on 5XXX series cards

Cheers

How do you swing fixed price electricity?  That's a sweet deal!

I have three rigs right now and building a fourth.  Expect to have 10 in the next month or two.  That could easily be a $900 power bill in LA, even with commercial rates.

I've asked the owner of this storage place if i could get up to 80 amps to support me growing to about 10 rigs.  We'll see what he's willing to do.  Boat storage is also a good idea.  Might check that if it this doesn't work.

Thanks Dargo.

Meanwhile, the owner of a climate controlled storage place says he can give me a storage unit with power, so I'll be checking that out in the next day or two

Thanks for the offer!

Let me give it some thought.  I'm going to meet with a guy who owns a storage place in LA that might be willing to do something for me.  I'll keep you posted

I bet you're paying more like $0.12/KWh in Florida, huh?

If you're serious, I just might consider it 

Thanks alans! 

@hmblm1245

If the place I find (if I find one) has Internet access of some kind, I'll just use that.  Worst case scenario is getting a 3G or 4G wifi modem.  They have them for about $50/month.

@alans

Interesting idea on renting a house and then subletting.  Could be more trouble than it's worth as you say.  Sorry to hear that you're getting out of the BTC racket.  I agree that it is a hassle to find a space and administer the systems.  I'm enjoying it though, and have enough free time to keep tinkering with it. 

Thought about that.  I'll have to give one of the places a call.

Thanks!