Can PRTG network monitor produce continously updating graphs?

a windows performance graph usually is started on the PC you want to get the statistics for and you usually just rune one instance of it.

PRTG is developed to monitor a large number of devices! A small scanning interval, in most cases does not give you more acuracy, but causes unnecessary load on your network and the devices.

It is only recommended for debugging and a limited number of sensors for a limited time.

PRTG Network Monitor front end is a web application. You will have difficulties with any website if you want a very small refreshing interval!

Regarding "usually just run one instance of it" - we run several dozen instances of it to monitor remote servers. I was hoping that PRTG Network Monitor could be used to replace those graphs.

PRTG Version 6 would do this so this is, unfortunately, another example where the "new" version of PRTG lacks some of the nice features of the old version.

In fact, I've seen many situations in PRTG Network Monitor where you ASSUME that people have long monitoring intervals (e.g., 30 seconds, etc.). How about those of us that monitor fewer devices but have more critical intervals (e.g., 1 - 5 seconds)? In many critical applications, 15 - 30 seconds is an eternity and is completely USELESS because the curves get smoothed out far too much.

In other words, your entire emphasis seems to be on "averages" but what I want is "peaks". For that you need very short intervals.

Actually, the standard PRTG 6 graphs were identical to the standard PRTG 8 graphs. Both graphs average values over time. In PRTG 6 it was possible to generate unaveraged graphs using the View -> Historic Data function. This option can now be found in PRTG 8 under Sensors -> View Historic Data. Beyond that, it is possible to define shorter scanning intervals (down to 1 second) under PRTG 8 (Setup -> System Administration -> System & Website) under the "Scanning Intervals" options. It is, however, not recommended to use such small intervals, particularly when monitoring a large number of sensors, seeing as this can cause issues not only with the monitoring functionality but also result in bandwidth saturation (each scan uses network resources, so the more requests are forwarded within a specific period of time, the more these resources will be necessary for the software's usage).

Last but not least: although small scanning intervals result in less "smoothed" graphs, even when using a small scanning interval the same are still being averaged. Only the historic data option (using raw values) displays the actual monitoring points as received by PRTG. How this affects the graphs of course also depends on the sensors used. Small scanning intervals might make sense with SNMP sensors, for example, but would certainly be overkill when monitoring NetFlow or Packet Sniffer sensors.

We personally recommend keeping your scanning intervals above 10 seconds. I'm afraid we can't offer support for smaller scanning intervals, seeing as these can lead to issues, as mentioned above. Nonetheless, you can certainly define and use these intervals.

With respect, I think you're wrong about PRTG 6. The PRTG 6 Windows GUI provided real-time smooth-scrolling graphs as opposed to static graphs that are refreshed at an interval. The smooth-scrolling graphs are MUCH easier to watch at faster refresh rates (no window "flashing"). As far as I can tell, this feature is NOT available in PRTG 8 and it makes PRTG 8 much less useful at faster refresh intervals.

I'll repeat my earlier comment: The customer must decide what monitoring intervals make sense (and manage the load on the server/network accordingly). Graphs at 5 - 30 seconds intervals are almost completely useless for displaying volatile and bursty network traffic. Again, PEAKS are important, AVERAGES are useless. PRTG 8, at least by default, has a strong emphasis on averages.

Another example: Bandwidth graphs that default to "Total" (in & out) bandwidth. This doesn't even make sense in a full-duplex world.

I'm sorry that it looks like PRTG 8 is not an improvement over PRTG 6 in these areas.

PRTG 8.3, due in 1-2 weeks, will automatically refresh the "live graph" on the "live graph"-tab at sensor interval. So you will see the data moving there!

Yes, there may be some things that PRTG 8 does not as well as PRTG 6. This is due to the fact that PRTG 6 was "only" a bandwidth monitoring software while version 7 and later can do a lot more. We had to do some sacrifices to cover more functionality.