Because unknown people on the internet using CC/Paypal are generally unreliable.

Exchanges that had PayPal transactions for BTC got burned due to high fraud rates and chargebacks.

There is even a warning on the exchange forum not to use credit card/paypal to BTC conversions.
http://forum.bitcoin.org/index.php?topic=14632.0

They are too easy to cancel so that you get BTC but the guy you paid to, gets nothing.

There's a global service for that already, Western Union.
Few if any bitcoin exchanges accept it though because it's a lot physical work for the owner.

You have to withdraw the cash in person so that's really not an option if you have large volume.

It can't be chargebacked unless you claim fraud.
And it's a much longer process than some scumbag frat boy lying to PayPal and clicking a few buttons.

The credit union who issued the Visa/Mastercard will invoke a police investigation and the scammer will be held criminally liable if he's found out to be lying
(i.e. the card wasn't stolen, gave it to a friend who cashed it out, CCTV camera proves he was there withdrawing it etc.)

Even then, you can't reverse cash. Once you send it in the mail, it's obviously gone for good. In fraud cases the credit union absorbs the risk.

Probability only evens out in the long term so it could turn out you missed out on a lot of short rounds and nearly double daily rewards while you were gaming (proportional pool luck).
Then again, you might've "saved" money by not participating in multi-hour rounds that only generated a few bitcents during the time you were gaming.

Really, the only way to mine without gambling is using a pay-per-share system like on Deepbit. It has a higher fee, but you get the same reward every single day (for the duration of that difficulty) given you always mine 80% of the day.

PPS doesn't care about pool luck, invalid blocks, long rounds etc...
You get paid for every single share day in & day out.

Install catalyst 11.6 and use dummy plugs (or plug all cards into monitor sockets on displays like TV's, pc screens etc)

Happened to me once on first boot when I set up a dual 6990 rig on Windows.

Switch PCI-e lanes with another card, wait until the microcode drivers (not AMD Catalyst)
are auto-installed by the OS.

After that you can put it in the old slot.

Then you should see both cores and any other GPU's on that system.


If you still fail to see all cores it could indicate the motherboard is not capable of delivering sufficient power to all GPU's on the board.

360 per core is actually pretty good.

I can't get my 6990 cores much past that without significant overclocking.
Even then it will hit about 380 max, maybe 800mhash/s total if I really tweaked around with the settings.

Consider that a 5970 is at least 100-150 bucks cheaper so it's a bargain if you find one.

I have ~13ghash now (sold off some graphics cards) and I quit soloing in the beginning of June. Before that, it generated 50 btc every now and then.

Pools are superior now for most miners in terms of reliability, maybe if you have 60+ ghash/s you could try soloing. More variance but since you are the size of a small pool, you'll get 50 BTC every few days at the least.

They don't make "any" graphics card with a 1x connector. All PCI-e graphics cards have a x16 connector.

There is a way to use them on x4, x8 and x1 lanes though; By using adapters.

Same thing. My withdrawal showed up in the bank account balance this morning.
It seems they send them out in batches.

That's not really going to happen considering they only entered production this month.
Hell, the 6990 just came out a few months ago.

Even now I'm waiting about 2+ weeks for a withdrawal.

Not a big deal otherwise, but I need it to pay electricity bills, lol.

My point is that pools like Slush and Deepbit have no incentive to steal the block reward.
They will earn a good amount of cash in the long run with their fees (2-3%). They generate many blocks every hour.

Since on this pool it might be weeks or months before anything is found & most people will only be mining for the extra rewards, there is a lucrative opportunity for the owner to just run with the single block after discovering people quit mining when the block is found.

Because it's highly likely it will be the only block the pool will ever find.

If price doesn't rise in the hundreds of dollars then it wont happen until FPGA/ASIC boards are released.
Assume a Radeon 5850 gets around 300mhash/s at 225 watts. That's 90,000 watts of constant power consumption for 120ghash/s

If electricity costs about $0.10 per kWh,
you are spending $216 dollars per day to generate 0.45 bitcoins.

If the price of 1 bitcoin is below $480 ($216 for 0.45) nobody is going to mine them on GPU's.

I don't. It's just a kid with an overactive imagination and a need for attention.

The DEA busted in your 'buddys' house and asked if he's the 'google or something'.

Then you woke up.

Yes they are, at least when it comes to pricing and fiat exchanges.

TH and Mt. Gox get more volume in a week than the other exchanges combined get in a year.

Other exchanges are practically meaningless with volumes ranging from 10 to 200 BTC per day, something that is crossed within seconds on Mt. Gox.

Profitability and your probability of finding blocks is mathematically constant, based on your hashing power and current difficulty.
Finding blocks or not finding blocks doesn't indicate anything.

Pools reduce your variance, but aren't any more "profitable" than solo in the long term, statistically speaking.

25+ in stock, 10 minutes later "out of stock".


Watercooled 6990's can push 830mhash/s per card easy, maybe even more if you cool the VRM. On a robust motherboard & PSU you can run 4 of these under Linux for 8 total GPU's = 3320 mhash/s per 1 rig.

Or, you could just buy 8 pieces of 6950's and need up to 2-4 power supplies, motherboards, CPU's, RAM sticks, casing, WLAN adapters etc. to run them. 5830's and 5850's are out of stock everywhere.

You can't just calculate $ per mhash.
You have to take in account the fact you need to build an entire system around the GPU, or multiple systems. A GPU doesn't run on it's own when you open the box.

Single mining operations will never reach tera/petahash performance with conventional GPU's or even clusters in data centers with massive amperage.

ASIC boards will overtake GPU's in power efficiency by at least 2012-2013, if not earlier. Devices hashing multiple hundred mhash/s at a few watts will become the norm once GPU mining becomes infeasible & mining will continue.

Why? Because market conditions will make ASIC mining favorable. Even if 120 ghash/s will only create 0.45 BTC per day in 2013, a farm of circuit boards creating that amount of BTC per day will only draw maybe 1kW of power and cost a few hundred dollars.

Price per BTC will probably not stagnate at $17 at that point either, due to demand & immense difficulty of creating new blocks.

I agree with Mike, that PSU is horrible.

It's the only component beside the GPU that actually matters for 24/7 use.

Spend the extra for a quality one, skimp on the RAM and processor.