6. Performance - Write

Previous to the Xbox, I had an external USB2 drive attached to my media center PC which stored all of the shared files. I have a wired 100 Mbps Ethernet and unfortunately there is no way to upgrade the networking on the Xbox to 1000 Mbps, otherwise I'm sure it would be the ultimate NAS.

As a very quick benchmark, I copied a 150 MByte file with the following results:

Computer A: internal drive to internal drive, same machine = 11 seconds Computer A: external USB2 hard drive to internal drive = 13 seconds Network copy, Xbox NAS to Computer A internal drive = 19 seconds Network copy, Computer B internal drive to Computer A internal drive = 19 seconds

Computer A: Athlon XP3200 Media Center PC with Windows MCE 2005 and 768 MB RAM
Computer B: Athlon XP1600 Laptop, with Windows XP Pro, 512 MB RAM

So reading from our converted Xbox is obviously slower than from a USB2 external drive, but about the same as reading from a networked XP share.

I also measured read and write file system performance for the device using the iozone tool as described here. All tests were run with the Media Center "Computer A" running iozone.

NOTE! How fast a computer can read or write data to a drive depends on many factors specific to the system running the test, so this test may not represent actual performance you'd see on your own system. The maximum theoretical data transfer rate one would expect to see on a 100Mbit network is around 12,000 kBytes/second, so any values that exceed that number appear as a result of caching behavior, not network speed.

Figure 1: Xbox NAS Write performance
(click image to enlarge)

Figures 1 and 2 show write performance using the modified Xbox and a networked Athlon XP1600 Laptop running Windows XP Pro with 512 MB RAM as the target drives being measured. While the peak cached speeds are both in the neighborhood of 300,000 kBytes/second, the Xbox maintains higher cached performance over a wider range of file and record sizes, giving it a write performance advantage.

Figure 2: PC to PC Write performance
(click image to enlarge)