IBM Cloud VPS Review

All grades are based on tests run by VpsBenchmarks on each VPS plan. There are 5 types of tests: web, sysbench, endurance, remote timings and network transfers. Each grade is the combination of one or more test metrics.

A grade is calculated in each on of 5 categories: web, cpu, disk, network and stability. Each category grade is made of one or more metrics chosen in relevant test types.

Given a metric for a plan and a test, the grade for that metric is determined relative to the same metric from all other plans. A plan with a metric in the top 18% of all plans will get an A, a plan with a metric in the bottom 18% will get an F. Relevant single metric grades are then weighted and combined to give a category grade.

Under the hood, a grade is a decimal number between 0.0 and 6.0.

The overall score is the average of the grades in all categories brought into the [0 - 100] range.

Note: The VPS plan price is not a factor in calculating the grades. More expensive plans with higher specs are likely to get higher grades than cheaper ones. This can be changed in the Screener by turning on the "price weighted" switch.

Web Performance

The Web Performance grade is made of the Web test average response time, 99th percentile response time and the maximum rate of requests without error.

Raw CPU Power

The Raw CPU Capacity grade is made of the Sysbench CPU test number of operations per second and of the Endurance test number of iterations per hour metric.

Performance Stability

The Performance Stability grade is made of the Web test average response time standard deviation, the difference between the 99th percentile and average response times and the Endurance test number of iterations per hour standard deviation.

Disk IO Performance

The Disk IO Performance grade is made of the Sysbench test sequential disk write speed and randow read/write speed.

Network Performance

The Network Performance grade is made of large file network upload and download transfer speeds.

Price Weighted Grades

The Screener and other pages offer the option to display "price weighted" grades. With this option turned on, a low price plan that has the same performance as a high price plan will be shown with higher grades.

The price weighted view tries to answer the following questions:

• What plans have the best value?
• How much performance do I get for every dollar I spend?

For low price plans, the grade "bonus" is proportional to the difference between its $30 and monthly price. The function used to calculate the bonus is designed to have a small impact on very low grades and maximum impact on medium to high grades.

Similarly, grades for high price plans are displayed lower when this option is turned on: the higher above $30 the monthly price is, the stronger the hit on the grades. In this case, the function is designed to have a small impact on excellent grades and maximum impact on medium to low grades.