The billed option provides for a base priority equal to that of the long-term investment option. An important distinction is that billed option investors will be charged for all NCU hours consumed whereas long-term investors may exceed their investment allocation when resources are available without incurring additional charges. This is the service offering that is recommended for researchers with frequent but unpredictable usage patterns and who are unable or unwilling to commit funds in advance.
To decide when a project is best served by the option of using resources by hourly rate, estimate the average number of NCU hours that the project will need in a month. If the total is less than 5,000 hours per month, corresponding to a monthly bill of $50 (5,000 x $0.01) or an annual bill of $600, then you are probably best served by the billed option. If the computational needs of the project exceed 5000 NCU hours, then the long-term option should be considered as it will offer more computing capacity at a lower rate with the additional advantage of exceeding your investment allocation when resources are available.
When grant funds are used to pay for computing resources, it is also important to consider requirements from the funding agency. Buying compute cores requires that the grant includes the acquisition of equipment in the budget. Computing at an hourly rate requires that funds are budgeted under the category of “Computer Services”. Please see Proposal Support or contact us if you have questions about how to budget for computing resources in your proposals.