Wow! What curious results.

How much work has previously been done determining the relationship between memclock and hash speeds?

The noob version is that hash speed is independent of memclock, so set memclock as low as possible to keep power consumption, heat generation and fan speeds nice and low. But these graphs suggest that's by no means the whole story.

The most interesting thing is the periodicity... what's up with that? Are you sure that's not an artifact of some kind (or in coarser language, a bug)?

Is your prospective vendor an l_mayhew2009 (or somesuch)? If so, that's the one. If you win it at a bargain basement price, and manage to get it working for a few bucks more, let me know so I can kill you and everyone you've ever loved with my thought rays congratulate you on your resourcefulness and enquire politely how you fixed it.

ETA: oh in our communications, the guy did reassure me that the white goo was thermal paste... which, considering how prominent it was, might easily be the cause of the problem for reasons D+T explained. OTOH he might have removed and reapplied it himself by now.

Just so's you can all sleep easily at night again, I did indeed return the card to the ebayer, and he refunded me toot sweet. Amusingly I now see he's reselling it on ebay! Though to be fair, he has made it clear that it's faulty ('for parts or not working' as the lingo goes there).

Thanks to everyone who prevented me from following my natural instinct to take it apart, get way out of my depth and spend far too much time and effort getting nowhere.

So, having done a bit of research over the last coupla months, I'm gonna make me a sweet miner. I've ordered a mobo with 4 PCIe x16's, it'll have risers, a 5970 on the end of each (delivered by the 5970 fairy), and all juiced up with a 1250W 80+ Gold PSU. Shitty CPU, cheapest ram, basic NIC and a BAMT stick, phoenix and phatk2. Oh yes, I know my onions.

This post is not about that miner.

This post is about the cheap-ass £30 mobo I bought back in October when I'd just learned what a bitcoin was. I have had it running 2 5970's. I am going to give it a third. But I want to make sure I sew the pieces together properly.

It has two PCI slots, a PCIe x1 and a PCIe x16. The PCIe x16 has a riser and a 5970. That seems fine.

The PCIe x1 has a x1 to x16 riser with the other 5970 on it. That also seems fine. But could someone confirm for me that that's all OK? There's no power issues there, right? A x16 slot can supply 75W of power, but I dunno about a x1 slot.

Then there's the PCI slots. One of those has the network card. The other one is free... but not for long. My plan is to stick a PCI-PCIe16 adapter in there, like this one: http://www.virtuavia.eu/shop/pci-32-bits-1-x-pci-express-adapter-.html . Then have a x16 riser coming out of that, then stick the third 5970 (which I already have) on the end. Is there going to be a power issue here? The 5970 will get 225W fair and square from the 6-pin and 8-pin cables to the PSU. How much will it draw through the PCI slot? How much CAN it draw from the PCI slot? What will happen to the card if it can't get enough power? What will happen to the mobo if the card draws too much power? If one of these two misfortunes is to occur, how do I know which one it'll be?

Thanks for reading this far!

Over the last couple of months I have bought 4 used 5970s off Ebay, from different vendors, and I'm planning to get 3 more. 3 of the 4 have been fine, but the last one... grr.

It's an XFX Black edition if that makes any difference. The vendor mentioned there was a hairline crack in the backplate. There is, but I don't think it's causing the problem. More worrying was that I could see a couple of patches of white goo inside the card, just behind the backplate. They remind me very much of what I saw in a PSU that I apparently blew up.

If I try to set the card mining at any decent speed it packs up... the happy green light by one of the GPUs gets replaced by an angry red light near the fan.
When I set the clock speeds VERY low (mem and core both around 100 Mhz) it can mine, but as slowly as you'd expect. Looking at the GPU temps with atitweak, I can see that within seconds of starting to mine, the reported temperature rises rapidly, reaching maybe 100C over 30 seconds (and this is with the *shitty* clock speeds). This is despite the fan going at 100% and is the same for both GPUs. Running either GPU separately still gets it going at 100C and the other GPU, which is idle, gets to around 70C.

What's going on? Are the temperature sensors merely defective? But they do show the rapid cooling when I stop mining. So I think that somehow the heat is getting trapped in the GPUs and not being dissipated. Are the white goo blobs to blame? What are they and can I fix this?

Pics of the goo hopefully to follow soon.

Your social engineering still needs lots of practice. Sure, just like all scammers, you're not going to stop, you're just going to lie low until people have forgotten about you and then try again... but it really is a bit stupid to explain all this to your marks.

Lack of benzos, yes? 

Sorry, I didn't express myself clearly. I didn't mean to imply the act of social engineering is completely useless - for the 'social engineer' (aka 'hustler') it is clearly very useful. I meant that the use of the euphemism was completely pointless, as only a moron could, upon reading the words 'social engineering' and having an example described to them, fail to recognise what was really being described (namely deception).

ETA: btw apologies for the presumption, I haven't been at this forum long enough to get a feel for what's tolerated, but I can't help but feel that, with Bitcoin media coverage being all drugs this, kiddie porn that, and Silk Road the other, we really don't need to let scammers flourish. So I have reported this thread to the moderators. Hey, they might feel there's no harm in it, in which case so be it.

Only two trading strategies actually work consistently.

1) Buy and hold an index fund.

2) Be Warren Buffett.

The rest is merely the human propensity to insist on finding patterns in noise.

It's pretty bloody obvious that 'social engineering' is a (completely useless) euphemism for 'scamming'.

Another point that works in MtGox's favour (IF you trade a lot) is that their trading fee goes down in increments as your trading volume goes up. My fee is 0.5% at the mo, and would shortly go down to 0.46% if I trade a bit more soon. Having said that, I don't really intend to, as I've tried 'timing the market' (especially on that stupid January evening when the price went bouncing like crazy because of something Bitcoinica related), and had more failure than success (nothing too big either way). So for now I've just 'bought-and-held', in which case the MtGox volume savings don't really help.

I set up GBP accounts with both of them a few months ago (back when Intersango was still FREEEEE!!!1!1!!) and did a few toy transactions with them.

So far I have only withdrawn GBP from Intersango. In that case, if you specify a UK bank account, the transaction is also free in the sense above. I have not yet tried withdrawing GBP from MtGox but I understand that you can only do it by wire transfer, there will be a fee involved somewhere along the chain and I am worried about how much it will be.

Can anyone who's transferred GBP from MtGox to a UK bank account chime in and say how much it cost?