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).

_	Windows XP	Windows 7	Mac OS X 10.6	Ubuntu 11.10
_	(SP3)	Enterprise	Snow Leopard
Gabor	0	5	0	0
500-dot RDK	0	5	54	3
750-dot RDK	21	7	aborted	1174
1000-dot RDK	776	aborted	aborted	aborted
GPU	Radeon 5400	Radeon 5400	Radeon 2400	Radeon 5400
GPU driver	Catalyst 11.11	Catalyst 11.11		Catalyst 11.11
CPU	Core Duo 3GHz	Core Duo 3GHz	Core Duo 2.4GHz	Core Duo 3GHz
RAM	4GB	4GB	2GB	4GB

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

• longer runs (one per night!)
• a faster Mac
• a real-time Linux kernel