With larger patches the performance of vvvv might decrease.
Here are some hints to optimize the performance.

DeBug-mode

CTRL+SHIFT+F9 will toggle the mysterious DeBug-Mode
a value of unknown measuring unit gives you an idea about the performance needs of each node.
DeBugging itself also has some performance needs. Therefore notice that it is possible to select only few nodes.

SpreadCounts

Set SpreadCounts in unused subpatches / modules / parts of patches to zero.
especially when using nodes of Category Animation with large SpreadCounts e.g. Newton (Animation)

Unchanging Renderers

Always disable secondary GDI or EX9 renderers which are not needed or do not display changing scenes. If a Renderer (GDI) is used e.g. for Text rendering, always wire up the enabled pin to a Change (String) node, which will activate the Renderer only of the text is actually changing.

Update View

CTRL-U lets you toggle the update of vvvv's UserInterface.

Avoid using IOBoxes for monitoring

especially IOBox (String)s containing large strings like XML descriptions.

Keep Patches hidden

if their visibility is not important. ALT-3 is your friend. Docked Windows are NOT hidden even if they aren't visible.

quoting gregsn's remarks in a related vvvvorum thread:

"listening" Nodes

Some Nodes have to "listen" for events (e.g. MidiController (Devices) ). from officially unverified user observations is reported that one should avoid to use many instances of those nodes. better take effort from vvvv's unique feature spreads

"parsing" Nodes

like XPath (XML) or RegExpr (String) have some performance needs if they have to deal with larger inputs. in some situations you need their results only on startup of your patch. Hold their results with e.g. S H (String) and disable their input in the following frame.
better than parsing a large string (that doesn't change at all) once each frame with a complex formula.

Our fellow diki made a very interesting module with a related approach.

Regarding this try to make use Switch (Node) Input? to disconnect SetPatch (VVVV) and GetPatch (VVVV) from PatchAlias (VVVV) whenever it seems possible.

Boost node

Boost will increase vvvv´s thread priority in the operating systems. This sometimes allows you to get the last quantum of performance out of your computer. See Boost (VVVV)

Avoid too much subpatches

in large patches with massive use of subpatches/modules you better replace the subpatches/modules with "extracted patchlets".
vvvv evaluates faster then.

S/R nodes vs. links between nodes

• ->related vvvvorum thread

Preparing your system

• make sure to always use the latest drivers for your graphics card.
• remove windows services:http://www.overclockersclub.com/guides/windows_xp_services.php

PerfMeter for Renderer (EX9)

The Module PerfMeter (Performance Meter), which comes standard with vvvv, allows you to get some global performance information when running a Renderer (EX9) in full screen mode. See its helpfile to understand what is going on.