Upgrading RAM in Late Model 2009 iMac Is it worth upgrading an iMac late 2009 model to max RAM at 16gb for video editing/exporting? Currently to export a 3gb video file in Final Cut Pro it takes 1 - 1.5 hours to export the file. Is it worth it to upgrade the RAM or buy a new iMac ( was thinking this model)

Think its a late 2015 model which is the current one in store

21.5 inch

2.8GHz Processor 
1TB Storage

2.8GHz quad-core Intel Core i5 processor
Turbo Boost up to 3.3GHz

8GB of onboard memory, configurable up to 16GB

1TB hard drive1

Intel Iris Pro Graphics 6200

1920-by-1080 sRGB display
You have the perfect test setup here:


  iMac late 2009 model ... to export a 3gb video file in Final Cut Pro it takes 1 - 1.5 hours


You can restart your Mac and quit all the apps except FCP and open activity monitor. You can watch the memory usage during the export. If the memory pressure is green, then no amount of RAM will help speed up the export. 

Assuming RAM isn't the bottleneck, next to eliminate is the storage - watch the iops and data rates for read and write. That too is easy to benchmark - ssd gets higher iops than most single hard drive. The other answers have great advice and your bottleneck is likely CPU/GPU but you can measure precisely what you need with activity monitor.