cc2.8xlarge is the best in terms of price/ECU-hours. You get a whopping 60GB of RAM, 10Gbps network interface. Downsides are: EBS only, us-east-1 only.
Ah, it is indeed cheaper, but I'm getting different specific numbers: 240 cents/88 ecu-hr == 2.7 cents/ecu-hr on demand; less if reserved or spot. cc2.8xl is also in the Oregon and Ireland regions, but not others as far as I can tell.
1) Funny that scaling up to one of their largest instance types can improve bang-for-buck, on this metric at least. 2) I wish Amazon made it simpler to sort all this out.
1) Funny that scaling up to one of their largest instance types can improve bang-for-buck, on this metric at least. 2) I wish Amazon made it simpler to sort all this out.