WPF当前时间不使用调度程序

I'd like to know is there any other option to show current time without using DispatcherTimer? Unfortunately app need's to run in slow PC's and DispatcherTimer continuously increasing memory usage. I check that in WPF Performance Profiling Tool and that's true - CPU usage with 1sec timespan is ~5-15%. And becouse im using class to get time value and show that on label, it would be great if method to show could run without xaml-generated controls.I'd like to know is there any other option to s