Everything I playback in N5.5.3 suffers from audio glitches and dropouts.
I’m running at 48khz sample rate, 24bit resolution and 25fps.
My interface is an RME Fireface UFX set to a buffer size of 1024 samples which gives an input latency of 21.896ms and an output latency of 22.750ms, so the buffer size is not set too low in this instance.
If I play audio directly through the RME using the Totalmix software there are no glitches, so I don’t think the problems are related to the RME- it must be something within Nuendo.
I used to record everything at a sample rate of 44.1khz, but after converting older recording within N5 to 48khz the problems are still there.
New recordings made at 48khz all have the same problem.
The problem has been resolved by un-checking ‘Multi Processing’ on the Device Setup\VST Audio System menu!
There is very little help about this option, but it does state that "If activated, Nuendo will automatically distribute the processing evenly between all CPUs for optimum performance. This sounds like a plus to me. My system has 8x CPU’s so should benefit from the option being checked. Unfortumately, with it checked there are constant performance spikes that cause audio glitches.
With the option un-checked will all plugins just use a single CPU?
You’re right - I’ve just had a look around the forum and there are loads of posts about the 'Multi Processing ’ option - very confusing.
I’m monitoring the 8 CPUs now (numbered 0-7). With 'Multi Processing ’ un-checked most action seems to be in the first CPU ( 0 ) although there is still some activity in the other ones, although this may not have anything to do with Nuendo. Some of the CPUs ( 1, 3, 5 and 7) are marked as ‘Parked’ but there is still some movement on them.
With 'Multi Processing ’ checked there is more action in more of the CPUs, but the whole system staggers and glitches in an un-usable way.
Why could this be?
If ‘Multi Processing’ is supposed to spread the CPU load between all available CPUs, I wonder why it makes the system run so badly?
With only one usable CPU I’m asking myself why I need the other 7 !
have you also looked into the UAD software? I believe there’s a setting somewhere that can help out. Perhaps it got reset during a software update or something…?
Turning off the Multi-Processing option is the wrong way to solve the problem. You will only get a fraction of the performance from your processor.
There are several things to try. You may want to see if disabling HT (Hyper-threading) in you BIOS helps. While there are many benchmarks showing that HT on improves performance, my experience on my i7 system has shown improvement with HT off (much to my surprise). It is easy to change back and forth, so it is worth a shot.
You should also look into possibly disabling the Turbo-boost, C1, EIST etc. on you motherboard. Depending on which version of i7 you have, this could make a big difference. I believe this does not necessarily apply to the new Sandy Bridge versions.
Another thing to do is to run the DPC latency application. Search for DPC latency Checker and you will find it. You should be able to get under 100uS or better. I can get really low DPC numbers if I disable HPET in the BIOS, but I never saw any improvement in real world use and disabling HPET supposedly give you less accurate timing for things like MIDI, so I leave it on.
Video cards and their drivers could also be wreaking havoc for you. I’ve also improved things by changing the hard drive settings as well. Lots of things to mess with.