...
3) 4BTC? 5 S1's cost ~4.96BTC, have less chips and no PSU. This ain't a charity.
...
It still has to be a valid purchase though, the S1's made that and returned ROI reasonably quickly @6
BTC ROI will be 9-10 months away.
Slush's pool just added 220TH here the last couple of days and dropped my return per block down by 20%. With more power being added, 9-10 months away is generous and in scheme of things is way too long.
I noticed that, too.
Approx. cluster performance (30 min average): 1011315.784 Ghash/s
https://mining.bitcoin.cz/stats/Just a few minutes ago.
It was only 840 Thash/s last week. I guess they finally broke that 1 Ph/s mark. Funny because I was reading a post there last week that was talking about finally breaking the 1 Th/s mark. The mining industry is what is in a bubble right now. BTC will be just fine, but there are going to be a lot of bankrupt miners at the unemployment office over the next few years.