To modify printer timing behavior, edit:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Print

In the right hand pane, modify or add value from the following list of parameters:

FastPrintWaitTimeout type REG_DWORD Range: Milliseconds, Default: 240,000 (4 minutes)
When JobPrintsWhilstSpooling is enabled, the port thread must synchronize with the spooling application. This value determines how long the port thread waits before giving up, pausing the current print job, and moving to the next print job.

FastPrintThrottleTimeout type REG_DWORD Range: Milliseconds, Default: 2,000 (2 seconds)
When JobPrintsWhilstSpooling is enabled, some printers pause if they don't receive data for a timeout period (usually 15 seconds for a Postscript printer). To counteract this, the spooler throttles back on data sent to the printer when FastPrintSlowDownThreshold is reached. At that point, FastPrintThrottleTimeout causes 1 byte per defined period to be sent to the printer until the threshold defined by FastPrintSlowDownTheshold is exceeded.

FastPrintSlowDownThreshold type REG_DWORD Range: Milliseconds,
Default: FastPrintWaitTimeout divided by FastPrintThrottleTimeout

NetPrinterDecayPeriod type REG_DWORD Range: Milliseconds, Default: 3,600,000 (1 hour)
Specifies how long to cache a network printer. The cache is used to present the list of printers to the browser.

PortThreadPriority type REG_DWORD Default: 0
Allows you to set the priority of the port threads. These are the threads that send the output to the printers. Valid values are:
0 (Normal)
1 (Above normal)
0xFFFFFFFF (Below normal)

SchedulerThreadPriority type REG_DWORD Default: 0
The priority of a thread determines the order in which it is scheduled to run on the processor. Valid values are:
0 (Normal)
1 (Above normal)
0xFFFFFFFF (Below normal)

SpoolerPriority type REG_DWORD Default: 0
Sets the priority class for the print spooler. Valid values are:
0 (Normal)
1 (Above normal)
0xFFFFFFFF (Below normal)