Every U3 is different, play with the volt and freq combos until you find one that works best for your U3.  Be sure you're using a good power supply when you start upping the voltage.

Just let them keep wasting their money with the attack while we all mine on your back-ups, they'll stop eventually.

I think the 92G difficulty is scarring everyone and so we're seeing things slow down a bit.  I know it scares me when I look at it in my mining software...

If you bought it "new" it should have come with a power brick and USB cable, they are packaged that way from Bitmain.  Don't use the factory psu if you are overclocking, though, they tend to melt down.  Contact the seller and ask them to send it to you or to refund you part of the purchase price since it appears they may not have sold you a new device.

Or get a molex to barrel plug connector and power the U3 with a standard ATX psu (which is what most people do and what is recommended, I use the same psu that runs my S3+ to also power my U3).

I think we should allow for one roll-over, and if no one wins the second time it resets back to 0.1.  This is just supposed to be "for fun", so no reason for the prize to get crazy high and shorten the length of time we all can play.

On another note, a few months ago I posted that we might see 100G difficulty by the end of the year and most people scoffed at the idea; I wasn't too far off so far, and if things go the way they are going we will be well over 100G by 2016.

Yup, massive network growth was totally intended and planned for - that's why difficulty adjusts as it does.  If it wasn't intended then bitcoin would have been broken a long time ago.

Are you using the plug adapter?  It comes with a Chinese style plug that may work in some US outlets (if it's a tight fit), but you may just need the plug adapter.

What power supply are you using?  Did it ever hash before?  You may have burned out the factory psu, or it may be dead.

If the US pool goes down does the German pool keep running?  I'm asking because I would use the German pool as a fail-over if it is independent of the USA node, but if they are all linked then there's no reason for me to set it up that way.


Highest ever doesn't reset, and it's less than 1G.

I think you should try 800 max voltage and see how it runs.  Should be about as fast and a bit cooler.  You can also add a fan to the bottom of the U3 to help cool it, here's mine:



Yes, that looks good, although we could tell more if you did: then we could see your accepted shares and errors.  Zombie is normal for the U3, I suggest you check out the R1 as a controller and get it from CrazyGuy with his custom firmware, https://bitcointalk.org/index.php?topic=612390.0, it basically solves the zombie problem.

There are big farms like the one HaoBTC runs that are filled with S3s at less than $0.03/kW, so this isn't the end of the S3 by a long shot, we will still see multi-PH on the network from them.  Plus they are still a great machine for the hobbiest who seldom doesn't care about price to operate (and also doesn't make up a significant network percentage).

(pict from HaoBTC thread)

I think when you input a tx fee you may have done a total fee instead of fee/kb, because your tx fees are super small.  Those tx will get picked up eventually, I think you just need to wait it out.

Very cool, I use CrazyGuy's R1 for my U3, too.  I noticed that it's missing frequency 250, did you do a write up how to add missing frequencies?  I'd like to add that one back in, even though I run my U3 at 237.5 freq normally.

Nope, all systems are go.  It's a piss-poor piece of hardware is all, I'm just glad it hashed at all, the R1 as a controller has made it much more tolerable.

Oh, well that's cool that it will work like that.  Do you have the compac plugged into a hub, then the R1 (like it says to do for the U3)?

Also, how do you change the compac frequency while it's controlled by the R1?  The pull-down menu is populated with frequencies for the U3.

Well we all know that every U3 is it's own animal, so maybe you lucked out and got the only one ever made that actually performs better than advertised.  I, on the other hand, am left with one U3 and it won't hash over 45GH/s no matter what settings it has.

This pool would never, under ordinary circumstances, generate an empty block so your question is moot.  It only "just happens" if the pool software allows for it.  I am of the opinion, as are many others, that bitcoin itself should not allow "empty" blocks regardless of which pools are doing what, but that's another topic...

I think the timing of introducing LARGE amounts of hash power is something that they consider.  The longer you can mine at a lower difficulty the better your bottom line is.  I'm sure there's an analysis a large ASIC company can perform to show them just how much hash to add how fast in order to maximize their return.  When you are adding hundreds of petahash you better be looking at stuff like this or you're dumb at business.

Default with no command line options is 225, which I believe pulls more that 0.5A so verify your usb port can supply enough power.

Is there a firmware out there to update it to control the compac, wouldn't you need to install cgminer-gekko on the R1 first?

I run 3 instances of cgminer on my desktop and don't have any issues.  In fact, I think I actually noticed a performance increase from my various usb miners when I gave them each their own instances (one for compac sticks, one for nanofury sticks, one for U3 before I let the R1 take it).