Getsystemtimepreciseasfiletime Windows 7 Upd | 360p — 720p |

Increase system timer resolution:

timeBeginPeriod(1);  // Set to 1 ms
GetSystemTimeAsFileTime(&ft);
timeEndPeriod(1);

But this only improves to ~1 ms, not microseconds.

If you cannot install KB2813345, what are your options?

If you’re doing high-resolution timing on Windows and came across GetSystemTimePreciseAsFileTime, you might think it’s only for Windows 8 and later.
That’s partially true – but Windows 7 can use it, provided a specific update is installed. getsystemtimepreciseasfiletime windows 7 upd

This feature attempts to load the Windows 8+ API dynamically. If it fails (indicating Windows 7), it calculates the time by combining the steady performance counter with the system wall clock.

#ifndef SYSTEM_TIME_H
#define SYSTEM_TIME_H
#include <Windows.h>
// A wrapper function that behaves like GetSystemTimePreciseAsFileTime
// but is compatible with Windows 7.
void GetSystemTimePrecise_Win7Support(LPFILETIME lpSystemTimeAsFileTime); But this only improves to ~1 ms, not microseconds
#endif // SYSTEM_TIME_H

In the world of Windows system programming, time is more than just a number—it's a critical measure for performance profiling, high-frequency trading, database logging, and real-time data acquisition. For years, Windows developers relied on GetSystemTimeAsFileTime to obtain the current system time. However, this function, while accurate to the millisecond, often fell short for sub-millisecond requirements. If you cannot install KB2813345, what are your options

Enter GetSystemTimePreciseAsFileTime—a native Windows API function introduced to provide the highest possible resolution system time. But here’s the catch: originally, this function was exclusively available on Windows 8 and later. For developers and enterprise environments still running Windows 7 (and its embedded or server counterparts), this posed a significant barrier.

That barrier has a solution: a specific Windows 7 update that back-ports this precision time function. This article explores GetSystemTimePreciseAsFileTime, the required Windows 7 update, how to implement it, and critical compatibility considerations.

If you are shipping an application that targets Windows 7 and needs high-precision time:

Update: KB3033929 (or the later rollup KB3125574)

Microsoft backported GetSystemTimePreciseAsFileTime to Windows 7 via Security Update KB3033929 (released March 2015). This update was primarily released to address SHA-2 code signing support, but it also added several new APIs to the platform, including our high-precision time function.