This article applies to:
E-Prime 2.0
Detail
This article is dedicated to issues regarding critical timing using the E-Prime 2.0 software package. The data is presented by operating system and covers Windows XP, Windows 7, Windows 8, Windows 8.1 and Windows 10.
E-Prime 2.0 Millisecond Accuracy
E-Prime 2.0 reports timing accuracy to the millisecond precision level. Although E-Prime coordinates with the operating system and external devices to continually have control of the computer's execution, the operating system or other devices can take control at any time, which will cause an experiment to be suspended while the operating system task is completed. When these instances occur, E-Prime continues to accurately timestamp so that post-analysis can filter the trials correctly.
E-Prime 2.0 and Operating System Compatibility
As stated above, E-Prime reports timing accuracy to the millisecond precision level. For a full listing of Operating Systems that PST has thoroughly tested with E-Prime 2.0 for timing accuracy, please see the following Knowledge Base article: RELEASE INFO: Operating system (Windows 11, 10, 8.1, 8, 7, Vista, and XP) support in E-Prime [18652]. What exactly does this mean? For example, in the RefreshClockTest experiment used to verify and evaluate subject station timing capabilities, an E-Prime 2.0 supported machine is likely to have a larger maximum missed tick, but less of them in comparison to the same machine running an unsupported version of E-Prime 2.0. Using the 1% rule, almost all machines that meet the system recommendations will be capable of collecting critical trial data. PST encourages all machines expected to collect subject data to run the RefreshClockTest to verify their ability to collect critical trial data. For more information, please consult the Critical Timing Chapter in the E-Prime documentation.
Verify subject data stations in E-Prime 2.0 with RefreshClockTest
PST encourages all machines expected to collect subject data to run the RefreshClockTest to verify their ability to collect critical trial data. We have conducted thousands of timing tests on computers ranging from Pentium 60s - Pentium 500s with Pentium, Celeron, and AMD microprocessors on variety of cards and software methods. Our tests show that E-Prime 2.0 is accurate for millisecond precision timing. Windows takes over control of your computer at times to do operating system maintenance; this can be minimized but not blocked completely (remember the operating system has the highest priority). In our tests, normal programs miss millisecond events much of the time (e.g. miss rates on a Pentium 60 of 58% and Pentium 500 of 43%). This means that timing via conventional programming reading a microsecond clock can be wrong at the millisecond level most of the time. We have developed and implemented within E-Prime 2.0, special timing systems that deliver high timing accuracy (e.g., our millisecond tick miss rate is down to 0.005% on a mid-range Pentium 266, millisecond timing accuracy of 99.995%). Even more important, we have added a major innovation, Automatic Time Audit Logging, that records your timing precision in an easy to review/analyze method (e.g. mean display duration 109.4 ms, SD 0.49 ms). Using our Automatic Time Audit technology is likely the only way you can be sure of your timing accuracy without adding expensive specialized hardware. For detailed results of our timing tests and more information on what the results mean to you, please review TIMING: E-Prime Timing Test Results [27520].
Timing Benchmarks
Not all devices are created equal. PST has undergone a number of timing tests with a number of PS/2 and USB keyboards and mice. Our preliminary timing tests have shown a wide range of variability between devices of the same class. Sound cards are even more prone to the same variability.
E-Prime 2.0 Stimulus Device Response Timing Values
The following is a table of average and standard deviation results for the timing test paradigms used by PST to determine device latency. The experiment presented a square stimulus in the middle of the screen for 100 trials. The refresh detector connected to The Black Box Toolkit accepted the stimulus which in turned fired a stimulus event 100ms later to trigger electronic components connected to the devices to mimic a human response. In addition to the 100ms delay value from when the stimulus was presented a 5ms value was subtracted from the received RT value because the experiment station was running at 100hz and the stimulus was presented in the middle of the screen. For example, if the RT value was 225.45, the actual RT would be 225.45 - 100 - 5 = 120.45.
The experiment used E-Prime 2.0.10.353 in Fall of 2014. The Black Box Toolkit was used to collect and fire the response simulation values. The response box used was a PST Serial Response Box Model 200a. It was used connected via the UART COM port as well as using a Aten UC232A USB to Serial cable. Information about the paradigm used as well as specifics on the devices used or altered to simulate the responses and machines used to collect the data available upon request and intended to be posted to this timing site in future revisions. The same tests were run with an HP ZD7000 laptop running E-Prime 2.0 that collected the stimulus with a refresh detector attached to the SRBOX as well as simulating the response 100ms later. Unlike the subtraction for 1/2 the screen refresh, the latency values inherent via the SRBOX have not be subtracted from the E-Prime Timing Station tables which result in an approximate 2ms increase in the average values.
Since the original release of E-Prime in 2001, overall machine speed increases and enhancements have occurred in keyboard and mouse hardware technology to improve the average and stddev values of mouse and keyboard devices. The values reinforce that a device average and stddev values can vary between machine and operating system. In addition, as outlined in "How choice of mouse may affect response timing in psychological studies" (Plant R.R.; Hammond N.; Whitehouse T, May 2003), the timing characteristics of exact model devices (e.g. as extreme as purchasing two Microsoft USB Intellimouse from the same vendor) can also have varying timing characteristics.
HP Pavilion, AMD Ryzen 5 - Windows 11
Response Device | Statistic | Value (ms) |
Chronos (USB 3.0) | Average | 0.12 |
StdDev | 0.32 | |
Keyboard (USB Acer) | Average | 23.07 |
StdDev | 2.61 | |
SRBox (Serial Model 200a) | Average | 2.92 |
StdDev | 0.79 | |
Mouse (USB Dell) | Average | 25.87 |
StdDev | 3.00 | |
Parallel Port | Average | 0.08 |
StdDev | 0.28 |
NOTE: E-Prime 2.0 is not supported on Windows 11 (see RELEASE INFO: Operating system (Windows 11, 10, 8.1, 8, 7, Vista, and XP) support in E-Prime [18652]).
Dell Precision T3400 - Windows 10 | ||
Response Device | Statistic | Value (ms) |
Chronos | Average | 0.23 |
StdDev | 0.42 | |
Keyboard (USB Acer) | Average | 15.78 |
StdDev | 2.83 | |
SRBox (Serial Model 200a) | Average | 2.87 |
StdDev | 0.87 | |
InterexMouse | Average | 13.88 |
StdDev | 2.63 |
Antec Quad Core - Windows 10 | ||
Response Device | Statistic | Value (ms) |
Chronos | Average | 0.24 |
StdDev | 0.42 | |
Keyboard (USB Acer) | Average | 16.11 |
StdDev | 2.57 | |
SRBox (Serial Model 200a) | Average | 1.93 |
StdDev | 0.63 | |
InterexMouse | Average | 15.2 |
StdDev | 2.41 |
Surface Pro 3 - Windows 10 | ||
Response Device | Statistic | Value (ms) |
Chronos | Average | 0.32 |
StdDev | 0.47 | |
Keyboard (USB Acer) | Average | 15.21 |
StdDev | 2.66 | |
SRBox (Serial Model 200a) | Average | 2.86 |
StdDev | 0.77 | |
InterexMouse | Average | 14.58 |
StdDev | 2.34 |
Dell Precision 490 - Windows 8.1 | ||
Response Device | Statistic | Value (ms) |
Keyboard (USB Dell) | Average | 4.82 |
StdDev | 2.53 | |
Keyboard (USB Acer) | Average | 15.02 |
StdDev | 2.53 | |
SRBox (Serial Model 200a) | Average | 2.38 |
StdDev | 0.7 | |
SRBox (USB 2 Serial Model 200a) | Average | 2.46 |
StdDev | 0.71 | |
InterexMouse | Average | 21.91 |
StdDev | 5.15 |
Dell i7 - Windows 8 | ||
Response Device | Statistic | Value (ms) |
Keyboard (USB Belkin) | Average | 36.86 |
StdDev | 8.74 | |
Keyboard (USB Dell) | Average | 11.35 |
StdDev | 2.23 | |
Keyboard (USB Razor) | Average | 17.14 |
StdDev | 0.76 | |
SRBox (Serial Model 200a) | Average | 2.23 |
StdDev | 0.8 | |
SRBox (USB 2 Serial Model 200a) | Average | 2.55 |
StdDev | 0.54 | |
Parallel Port | Average | 0.33 |
StdDev | 0.94 | |
Intellimouse USB | Average | 17.04 |
StdDev | 2.35 | |
InterexMouse | Average | 14.45 |
StdDev | 2.38 |
Gateway FX6850-51 - Windows 7 | ||
Response Device | Statistic | Value (ms) |
Keyboard (USB Belkin) | Average | 35.92 |
StdDev | 8.35 | |
Keyboard (USB Dell) | Average | 10.53 |
StdDev | 2.21 | |
Keyboard (USB Acer) | Average | 15.1 |
StdDev | 2.67 | |
Keyboard (USB Razor) | Average | 17.06 |
StdDev | 0.8 | |
SRBox (Serial Model 200a) | Average | 2.33 |
StdDev | 0.69 | |
SRBox (USB 2 Serial Model 200a) | Average | 2.27 |
StdDev | 0.7 | |
Parallel Port | Average | 0.41 |
StdDev | 0.5 | |
Intellimouse USB | Average | 17.08 |
StdDev | 2.58 |
Dell Precision WorkStation 340 - Windows XP | ||
Response Device | Statistic | Value (ms) |
Keyboard (USB Acer) | Average | 16.2 |
StdDev | 2.52 | |
Keyboard (USB Belkin) | Average | 36.8 |
StdDev | 8.28 | |
Keyboard (USB Dell) | Average | 12.4 |
StdDev | 3.69 | |
Keyboard (USB Razor) | Average | 18.51 |
StdDev | 0.84 | |
SRBox (Serial Model 200a) | Average | 2.16 |
StdDev | 0.69 | |
SRBox (USB 2 Serial Model 200a) | Average | 1.53 |
StdDev | 0.5 | |
Parallel Port | Average | 0.22 |
StdDev | 0.65 | |
Intellimouse USB | Average | 22.04 |
StdDev | 2.88 |
Sound Startup Latency Tests
E-Prime 2.0 reports millisecond accurate timing. This does not mean that E-Prime 2.0 is capable of making hardware do things it cannot. See article AV: Sound Latency - Not all sound cards provide optimal millisecond timing [17206] for background information on sound latency.
PST encourages using external equipment to determine the startup latency of your sound card. For our tests, we collected data using a Black Box Toolkit version 2 (BBTK v2) connected to various computers. Each experiment computer generated a sound as well as a parallel port pulse that was detected by the BBTK's microphone and line in respectively. There were a total of 18 sounds and port pulses collected for each session. The experiment paradigm used white noise files that were set to 2 channels, 16 bit, and 44.1Khz. The parallel port pulse was sent at the start of the SoundOut object in the experiment paradigm. Since parallel port pulses have been shown to have extremely low latency, the receipt of this pulse represented the time that the sound was sent from E-Prime to Windows for processing. This was compared to the time that the BBTKv2 received the sound through the experiment computer's speakers. The difference in these two times represented the sound startup latency, that is, the amount of time that Windows, the sound card, and the speakers processed the sound before it was audible.
As a result of our tests for the various operating systems can be found on the charts below. Keep in mind that we have tested multiple sound cards and APIs on computers of varying functionality.
Adapter | Type | Machine | Operating System | Driver | API/Expected Latency | Mean (ms) | StdDev | Min (ms) | Max (ms) |
OnBoard | n/a | HP Pavilion - AMD Ryzen 5 | Windows 11 | ASIO | 4.34 | 0.38 | 3.63 | 5.06 | |
OnBoard | n/a | HP Pavilion - AMD Ryzen 5 | Windows 11 | DirectSound | 37.10 | 3.11 | 32.54 | 63.30 | |
OnBoard | n/a | HP Pavilion - AMD Ryzen 5 | Windows 11 | Core Audio | 6.29 | 0.96 | 4.65 | 8.05 | |
Chronos | n/a | HP Pavilion - AMD Ryzen 5 | Windows 11 | Chronos | 0.84 | 0.01 | 0.79 | 0.89 | |
OnBoard | n/a | Antec Quad Core | Windows 10 | ASIO | 6.27 | 0.62 | |||
OnBoard | n/a | Antec Quad Core | Windows 10 | DirectSound | 36.79 | 3 | |||
OnBoard | n/a | Antec Quad Core | Windows 10 | Core Audio | 15.69 | 2.94 | |||
Chronos | n/a | Antec Quad Core | Windows 10 | Chronos | 1.07 | 0.31 | |||
OnBoard | n/a | Surface Pro 3 | Windows 10 | ASIO | 7.4 | 0.52 | |||
OnBoard | n/a | Surface Pro 3 | Windows 10 | DirectSound | 37.29 | 3.79 | |||
OnBoard | n/a | Surface Pro 3 | Windows 10 | Core Audio | 15.97 | 2.96 | |||
Chronos | n/a | Surface Pro 3 | Windows 10 | Chronos | 0.42 | 0.12 | |||
OnBoard | n/a | ASUS M32 | Windows 10 | ASIO | 6.21 | 0.52 | |||
OnBoard | n/a | ASUS M32 | Windows 10 | DirectSound | 209.18 | 26.63 | |||
OnBoard | n/a | ASUS M32 | Windows 10 | Core Audio | 16.11 | 2.75 | |||
Chronos | n/a | ASUS M32 | Windows 10 | Chronos | 0.47 | 0.08 | |||
OnBoard | n/a | Dell Precision T3400 | Windows 10 | ASIO | 5.75 | 0.72 | |||
OnBoard | n/a | Dell Precision T3400 | Windows 10 | DirectSound | 33.9 | 4.23 | |||
Chronos | n/a | Dell Precision T3400 | Windows 10 | Chronos | 0.56 | 0.11 | |||
OnBoard | n/a | Dell i7 | Windows 8 | DirectSound | 44.5 | 5.69 | 36.1 | 74.16 | |
OnBoard | n/a | Dell i7 | Windows 8 | Core Audio | 6.26 | 0.85 | 5.15 | 7.41 | |
OnBoard | n/a | Dell i7 | Windows 8 | ASIO | 6.18 | 0.45 | 5.26 | 7.08 | |
Sound Blaster Xi-Fi | PCIe | Dell i7 | Windows 8 | Core Audio | 27.31 | 3.16 | 21.85 | 32.53 | |
Sound Blaster Xi-Fi | PCIe | Dell i7 | Windows 8 | ASIO | 17.1 | 0.41 | 16.28 | 17.8 | |
OnBoard | n/a | Dell Precision 490 | Windows 8.1 | DirectSound | 43.89 | 4.26 | 34.66 | 52.14 | |
OnBoard | n/a | Dell Precision 490 | Windows 8.1 | Core Audio | 6.26 | 0.97 | 4.62 | 7.99 | |
OnBoard | n/a | Ad Hoc Quad Core | 7x64 | HDAudio | DirectSound | 40.733 | 4.217 | 34 | 49 |
OnBoard | n/a | Ad Hoc Quad Core | 7x64 | HDAudio | Core Audio 3ms | 5.533 | 1.06 | 4 | 7 |
OnBoard | n/a | Ad Hoc Quad Core | 7x64 | HDAudio | ASIO4ALL 4ms | 6.071 | 0.616 | 5 | 7 |
Sound Blaster SB0880 X-Fi | PCIe | Ad Hoc Quad Core | 7x64 | HDAudio | DirectSound | 55 | 5.306 | 50 | 71 |
Sound Blaster SB0880 X-Fi | PCIe | Ad Hoc Quad Core | 7x64 | HDAudio | Core Audio 3ms | 3.643 | 1.008 | 2 | 5 |
Sound Blaster SB0880 X-Fi | PCIe | Ad Hoc Quad Core | 7x64 | manufacturer | DirectSound | 344.267 | 830.216 | 119 | 3345 |
Sound Blaster SB0880 X-Fi | PCIe | Ad Hoc Quad Core | 7x64 | manufacturer | Core Audio 3ms | 28.214 | 3.017 | 23 | 32 |
Sound Blaster SB0880 X-Fi | PCIe | Ad Hoc Quad Core | 7x64 | manufacturer | ASIO4ALL 4ms | 16.714 | 0.611 | 16 | 18 |
Sound Blaster SB0790 X-Fi | PCI | Ad Hoc Quad Core | 7x64 | manufacturer | DirectSound | 142.2 | 12.359 | 134 | 186 |
Sound Blaster SB0790 X-Fi | PCI | Ad Hoc Quad Core | 7x64 | manufacturer | Core Audio 3ms | 18.6 | 3.043 | 15 | 23 |
Sound Blaster SB0790 X-Fi | PCI | Ad Hoc Quad Core | 7x64 | manufacturer | ASIO4ALL 4ms | 357.143 | 0.864 | 356 | 359 |
Asus Xonar DG | PCI | Ad Hoc Quad Core | 7x64 | manufacturer | DirectSound | 69.643 | 1.277 | 68 | 72 |
Asus Xonar DG | PCI | Ad Hoc Quad Core | 7x64 | manufacturer | Core Audio 3ms | 26.4 | 2.063 | 23 | 29 |
Asus Xonar DG | PCI | Ad Hoc Quad Core | 7x64 | manufacturer | ASIO4ALL 4ms | 367.786 | 0.802 | 366 | 369 |
HT Omega Striker 7.1 | PCI | Ad Hoc Quad Core | 7x64 | manufacturer | DirectSound | 88.071 | 3.025 | 83 | 93 |
HT Omega Striker 7.1 | PCI | Ad Hoc Quad Core | 7x64 | manufacturer | Core Audio 3ms | 25.071 | 1.685 | 23 | 28 |
HT Omega Striker 7.1 | PCI | Ad Hoc Quad Core | 7x64 | manufacturer | ASIO4ALL 4ms | 366.714 | 0.914 | 365 | 368 |
OnBoard | n/a | Dell Precision T3400 | 7x64 | HDAudio | DirectSound | 44.714 | 8.416 | 35 | 70 |
OnBoard | n/a | Dell Precision T3400 | 7x64 | HDAudio | Core Audio 3ms | 8.214 | 1.122 | 7 | 10 |
OnBoard | n/a | Dell Precision T3400 | 7x64 | HDAudio | ASIO4ALL 4ms | 6.643 | 0.929 | 5 | 8 |
OnBoard | n/a | HP Pavilion dv7t-1000 laptop | 7x64 | HDAudio | DirectSound | 47.357 | 3.795 | 43 | 53 |
OnBoard | n/a | HP Pavilion dv7t-1000 laptop | 7x64 | HDAudio | Core Audio 3ms | 6.214 | 1.051 | 5 | 8 |
OnBoard | n/a | HP Pavilion dv7t-1000 laptop | 7x64 | HDAudio | ASIO4ALL 4ms | 6.267 | 0.458 | 6 | 7 |
OnBoard | n/a | Gateway FX6850-51 | 7x64 | DirectSound | 44.53 | 7.2 | 35.15 | 84.73 | |
OnBoard | n/a | Gateway FX6850-51 | 7x64 | Core Audio | 6.02 | 0.51 | 4.92 | 7.04 | |
OnBoard | n/a | Gateway FX6850-51 | 7x64 | ASIO | 6.06 | 1.04 | 4.28 | 7.97 | |
Sound Blaster Xi-Fi | PCIe | Gateway FX6850-51 | 7x64 | DirectSound | 127.84 | 1.95 | 22.07 | 31.96 | |
Sound Blaster Xi-Fi | PCIe | Gateway FX6850-51 | 7x64 | Core Audio | 28.24 | 1.95 | 22.07 | 31.96 | |
OnBoard | n/a | Ad Hoc Quad Core | Vista x86 | HDAudio | DirectSound | 58.4 | 7.278 | 53 | 83 |
OnBoard | n/a | Ad Hoc Quad Core | Vista x86 | HDAudio | ASIO4ALL 4ms | 19.786 | 2.806 | 15 | 24 |
SB0880 X-Fi | PCIe | Ad Hoc Quad Core | Vista x86 | HDAudio | DirectSound | 58.933 | 5.535 | 53 | 76 |
Sound Blaster SB0880 X-Fi | PCIe | Ad Hoc Quad Core | Vista x86 | HDAudio | Core Audio 90ms | 136.357 | 29.705 | 92 | 177 |
Sound Blaster SB0880 X-Fi | PCIe | Ad Hoc Quad Core | Vista x86 | manufacturer | DirectSound | 129.667 | 24.307 | 120 | 217 |
Sound Blaster SB0880 X-Fi | PCIe | Ad Hoc Quad Core | Vista x86 | manufacturer | Core Audio 3ms | 26.8 | 3.509 | 22 | 32 |
Sound Blaster SB0880 X-Fi | PCIe | Ad Hoc Quad Core | Vista x86 | manufacturer | ASIO4ALL 4ms | 17.286 | 0.611 | 16 | 18 |
Asus Xonar DG | PCI | Ad Hoc Quad Core | Vista x86 | manufacturer | DirectSound | 69.2 | 1.146 | 68 | 72 |
Asus Xonar DG | PCI | Ad Hoc Quad Core | Vista x86 | manufacturer | Core Audio 3ms | 26.867 | 1.685 | 24 | 30 |
Asus Xonar DG | PCI | Ad Hoc Quad Core | Vista x86 | manufacturer | ASIO4ALL 4ms | 367 | 0.756 | 366 | 368 |
OnBoard | n/a | Ad Hoc Quad Core | XP x86 | default | DirectSound | 29.4 | 0.986 | 27 | 31 |
Sound Blaster SB0880 X-Fi | PCIe | Ad Hoc Quad Core | XP x86 | manufacturer | DirectSound | 11.667 | 0.488 | 11 | 12 |
Asus Xonar DG | PCI | Ad Hoc Quad Core | XP x86 | manufacturer | DirectSound | 69.133 | 1.642 | 67 | 72 |
OnBoard | n/a | Dell Precision Workstation 340 | Windows XP SP3 | DirectSound | 0.931 | 0.039 | 0.82 | 1.03 | |
Sound Blaster Xi-Fi | PCI | Dell Precision Workstation 340 | Windows XP SP3 | DirectSound | 69.56 | 2.45 | 69.09 | 86.54 | |
Sound Blaster Xi-Fi | PCIe | Dell Precision Workstation 340 | Windows XP SP3 | DirectSound | 69.191 | 0.97 | 66.96 | 71.64 |
NOTE: E-Prime 2.0 is not supported on Windows 11 (see RELEASE INFO: Operating system (Windows 11, 10, 8.1, 8, 7, Vista, and XP) support in E-Prime [18652]).
Paradigm
The paradigm used on the E-Prime side was the SoundExperimentStation.es2 file. The sound devices were set at 2 channels, 16 bit, 44.1Khz. A white noise sound file was used. Event generation file used on the BBTKv2. The results are from 24 trials per subject/session. E-Prime 2.0.10.353 (Windows XP, 7, 8, 8.1) or 2.0.10.356 (Windows 10) was used. Hyperthreading was turned on all computers. The MSCONFIG diagnostic mode was used to shut down background applications and services.
See Also:
TIMING: E-Prime 3.0 Timing Data [24332]
TIMING: E-Prime 1.2 Timing Data [19580]
TIMING: Machine configuration, design, or faulty components may result in bad timing data [18014]
RELEASE INFO: Operating system (Windows 11, 10, 8.1, 8, 7, Vista, and XP) support in E-Prime [18652]
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