Comparing Operating Systems under PsychoPy^®¶

This is an attempt to quantify the ability of PsychoPy^® draw without dropping frames on a variety of hardware/software. The following tests were conducted using the script at the bottom of the page. Note, of course that the hardware fully differs between the Mac and Linux/Windows systems below, but that both are standard off-the-shelf machines.

All of the below tests were conducted with ‘normal’ systems rather than anything that had been specifically optimised:

• the machines were connected to network

• did not have anti-virus turned off (except Ubuntu had no anti-virus)

• they even all had dropbox clients running

• Linux was the standard (not ‘realtime’ kernel)

No applications were actively being used by the operator while tests were run.

In order to test drawing under a variety of processing loads the test stimulus was one of:

• a single drifting Gabor

• 500 random dots continuously updating

• 750 random dots continuously updating

• 1000 random dots continuously updating

Common settings:

• Monitor was a CRT 1024x768 100Hz

• all tests were run in full screen mode with mouse hidden

System Differences:

• the iMac was lower spec than the Windows/Linux box and running across two monitors (necessary in order to connect to the CRT)

• the Windows/Linux box ran off a single monitor

Each run below gives the number of dropped frames out of a run of 10,000 (2.7 mins at 100Hz).

I’ll gradually try to update these tests to include:

• longer runs (one per night!)

• a faster Mac

• a real-time Linux kernel