[time-nuts] PCI-E Serial Card For Windows NTP?

Hal Murray hmurray at megapathdsl.net
Thu Jun 25 14:13:52 EDT 2015

I know next-to-nothing about Windows.

Serial ports are pretty standard.  I'd get the cheapest card.  I'd probably 
pay a bit more for a second port.  It might be handy tomorrow.

One difference between chips is the depth of the FIFO.

PCI card now come in two heights.  Make sure you get the right one.  The 
short ones don't have room for a second connector.  (Some cards come with two 
face plates.  You can swap in/out the other one if you can use a screwdriver.)

The other thing to keep an eye on is interrupts from the Gigabit ethernet.  
With a lot of short packets, you can get in trouble spending all your CPU 
time in the interrupt handler.  Some hardware is setup to batch interrupts.  
The idea is to delay an interrupt for a while in hopes that more packets will 
arrive and get processed as a batch.  You may want to turn that off.  It's a 
tradeoff between latency and CPU usage.  You may be able to measure it with 
something like ping.

These are my opinions.  I hate spam.

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