5 - 30 minutes
Sometimes my Mac "hung". The software I used needed at least 4 Gb Memory, but preferred 8 Gb.
I replaced the RAM Chips by 2 x 8Gb Ram Chips and the standard Hard Drive by the SSD Hybrid one.
Everything was explained very clearly : I had no problems to fix it.
1 TB SSD Hybrid 2.5" Hard Drive
PC3-10600 8 GB RAM Chip
TR6 Torx Security Screwdriver