Formula
The network uses megabits. The disk uses megabytes. Both cover the same decimal gigabytes:
seconds = GB × 1,000,000,000 × 8 / Mbps / 1,000,000 + GB × 1,000,000,000 / MB/s / 1,000,000
The download page is only the first term. This page adds the disk.
Assumptions
- The download finishes before the write, so the times add.
- The size written equals the size downloaded.
- Units are decimal.
Worked example
An 80 GB game at 100 Mbps, written at 200 MB/s, is ready in 1:53:20.
Input definitions
- Download speed
- Megabits per second on the connection.
- Disk write
- Megabytes per second the drive can store.
Limitations
This is a planning figure from the numbers you type. It is not a measurement of a network, a camera, a printer, or a power supply.
Questions
Why are the two speeds in different units?
Connections are sold in megabits. Drives are described in megabytes. The formula converts each one.
What if the installer also unpacks?
That extra work is not in the two terms. The page is download plus a straight write.