With several vendors offering cloud compute, it is becoming increasingly complex to identify which cloud instance type is most cost effective for your needs. To help find the right cloud for your workloads, we have compiled a comparison of 34 instance types available from 4 cloud providers. The comparison provides pricing, which includes reserved pricing if available, and three key metrics to assess the cost effectiveness of this instance type for different workloads:

  • Price per virtual core per month - used to evaluate the cost effectiveness of the processing power of the instance type
  • Price per GB disk per month - used to evaluate the cost effectiveness of disk for the instance type
  • Price per GB memory per month - used to evaluate the cost effectiveness of memory for this instance type

Result: Processing

Rackspace and Amazon offer the most cost effective options for compute, with several instance types in the $40-$50 range per virtual core per month. For example, the Rackspace 1024MB RAM 40GB Disk instance comes in at $43.20 per virtual core per month. An Amazon m1.small is also highly competitive, coming in at $44.01 per core per month. Rackspace has several instances on the high side as well, with the 30720MB RAM 1200GB Disk instance costing $1296.00 per virtual core per month.

Result: Disk

Amazon dominates the category for cost effective local disk for an instance, with a price of $0.21 per GB per month for several instances, including the m1.large and m1.xlarge. On the extreme high side of cost per disk we have Microsoft, with $1,478.44 per GB per month for its ExtraSmall instance (note: this is skewed by the fact the Azure PaaS model expects the usage of BLOB storage instead of local disk).

Result: Memory

Amazon provides the most cost effective options for memory, with several instance types in the $13-14 per GB per month range, including the m2.xlarge, m2.2xlarge, and m2.4xlarge instance types. The best in the category is the Amazon cc2.8xlarge, which comes in at $13.03 per GB per month. IBM comes in on the high side, with 7 instances pricing between $53-86 per GB per month, including the 64-bit Copper, Bronze and Platinum instance types.

Instance Type Comparison

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Up until recently, there has never been a choice in public clouds, so direct comparisons were mostly academic. Most of us know the reputations of the available clouds: Rackspace for outstanding support, Amazon for features and cost, IBM for enterprise, and Microsoft for Windows platform. But with increasing standardization in the base offerings of public clouds, consumers now have the ability to choose the cloud that best suits their workloads.

We hope this view into compute will help you better understand what cloud is right for your workloads, allowing you to be on the winning side in the battle of the public clouds.


Our comparison requires the following Surgeon General warnings:

  • No clouds were hurt in the making of this comparison.
  • To standardize reserved pricing, we have calculated prepays into actual hourly and monthly costs, which means the prepay has been amortized into the hourly or monthly cost.
  • The monthly costs assume instances are running 100% for the month.
  • The comparison uses Linux for all clouds except Microsoft Azure, which has no Linux support.
  • We have arbitrarily used 1/4 virtual core as a default for instance types that share a virtual core with other users. This was not based on actual performance metrics.
  • _IBM SmartCloud pricing is based on Red Hat Enterprise Linux pricing. _
  • The Amazon reserved pricing is based on a 1 year prepay for moderate use.
  • The comparison is focused exclusively on costs. For a complete view of view of price to value, we will add performance metrics in a future update.

Please let me know of any flaws with my comparison and I will make updates. Here is a link to the full spreadsheet: cloud_instance_pricing.xls.