Refund has arrived, thanks, and keep up the good work with the app.

Would like to see some alt-currencies added one day, although I guess the information available is not as rich as it for btc.

Using TomsHardware figures, the R9 280x consumes 255W, while the 7950 consumes 188W. Let's take something a bit less than the top figure from the mining comparison page, and you get, say, 780 kh/s for the R9 280x, and 700 for the 7950

700/188 = 3.72 kh/s/W
780/255 = 3.05 kh/s/W

So, if you accept the performance selections I chose, the 7950 is still the superior card (by a fair margin, I'd say). Of course, there are other factors, such as the limited number of cards you can get in a rig, and of course, the price. The R9 280x is a bit pricier, but it seems most people are shifting to the R9 280x because of the extra hashes per rig.

Bittylicious seem easy to buy bitcoins, but selling them again seems much harder. I can't see any instructions for selling them again, short of becoming a formal "seller"?

As the other poster indicated, when it comes to GPU mining rigs, the CPU is irrelevant. A celeron will do the job. You'll want a motherboard which can handle 2+ GPU's, and a solid PSU. A GPU sucks around 200W, depending on the card, so a 760W can probably handle two GPU's comfortably, but not three. So you may want to consider restarting your quest

As for the train leaving the station, maybe. A 1 mh/s system will probably earn just under $10 a day at the moment, if you're mining the alt-currencies (not LTC), so maybe $300 a month (this is not considering electricity costs). That will pay off your equipment fairly quickly, so it seems a reasonably good investment still. Admittedly, these returns are around half what they were 4-6 weeks ago. I don't think anyone really knows what's going to happen, though. Those daily rates could go up, they could go down. Today they're more than they were yesterday, but less than they were a week ago.

Have sent a PM

While I appreciate that having all this money in their system and having it difficult to access is distressing to you, I don't think there is anything wrong with what they are doing. They have indicated that you need to provide certain verification documents, you admit you can readily provide them, but do not wish to do so for obscure reasons (related, as far as I can gather, to inconvenience, politics and principle). Well, that is your right of course, but I fail to see how you can sue them or defame them or in any way legitimately criticize them. The fact that other institutions accepted your documentation is irrelevant. They are not the documents that MtGox require. They have terms and conditions which you presumably could and should have read prior to depositing your coins with them.

Will do so shortly, in the meantime, are there any particular tests that you'd like me to run on 4.4 tablet that you can think of?

I've occasionally mined this coin, when it's difficulty has dropped really low. However, it's quite a scary coin, because the client problems described in this thread. Nevertheless, I can confirm that I am able to mine at the various pools, and have coins transferred to my wallet, and am able to transfer them from my wallet to cryptsy. The xfer to cryptsy took over 48 hours, which was a little alarming, but it did eventually succeed. Sadly, it's now worth about 1/10th of what it was a month ago, so not really worth selling at the moment, but the technology is functional.

I've occasionally mined this coin, when it's difficulty has dropped really low. However, it's quite a scary coin, because the wallet client appears to be a little broken, and keeps moaning about "checkpoint out of date". Nonetheless, I can confirm that I am able to mine at the various pools, and have coins transferred to my wallet, and am able to transfer them from my wallet to cryptsy. Be warned, however, that the transfers can take a long time. The xfer to cryptsy took over 48 hours, which was a little alarming.

The impression I have from my research is that mining on mobile devices is a bad idea. This includes laptops, and of course, tablets and phones. These devices are not really built for long periods of sustained heat, and the components are likely to start failing pretty soon. This is particularly a problem as they are much less modular than desktops, and replacing the CPU or GPU on a mobile device is basically impossible.

Hi, I'd love the pro version.

I've tested the free version on my Nexus 7, running 4.4, and it works great.

Sancho, your plan is flawed. The GTX 670 can do about 200 kh/s, the 7990 can do over 1000 kh/s. So keep the GTX670 as your display driver and use the 7990 to mine. Of course, whether you can run AMD and Geforce on the same computer, which is probably what you're really asking, is harder to say.

Lensgrabber, Antminers are tuned to do SHA-256 calculations, which is the Bitcoin algorithm. A few other coins to this as well, but not Litecoin or most of the new coins. Are you saying you can get the Antminer to do 100kh/s on LiteCoin? That's pretty good, altho it depends on which one you're talking about. Are you talking about the basic USB one which retails for around $70? Or the upper end ones which go for around $8,000?

I'm mining a day or so on all the new currencies as they come out, just in case, although there seems little point in most of them. Doge is proving remarkably successful, as it seems to be the only one, oddly, given its peculiar origin, that has built up a community of apps, sites, trading, utilities and so on. It's the one I'm the most optimistic about, at this stage, even though it seems a meme-based currency should have short shelf-life. Probably helps that it wasn't pre-mined (as far as I can tell).