Both hard drives and RAM have got very cheap over the last few years - gone are the days when ad agencies would get broken into and all the RAM was stolen out of the Macs (aka a RAM raid)! I remember when I got my first memory upgrade of 16mb and it cost me nearly UK 100 pounds!
Anyway, enough sad old memories. The point is that same is true now as back in the day - buy as much RAM as you can afford because lets face it, you can never have too much RAM when it comes to Photoshop! When Photoshop (or indeed any other application) has used all the RAM available, that when things really start to slow down - as it then starts to use your hard drive as memory - usually referred to as a scratch disk. Photoshop has a very efficient memory management system, but the simple fact is that hard drive access speeds are far slower than RAM.
You will feel a very significant drop in performance once you RAM has run out and you start using your hard drive as a scratch disk. There are lots of ways to ensure Photoshop runs as fast as possible, so here are some important tips to ensure you can work the fastest you can:
Hardware
-It goes without saying you want the fastest computer/processor you can afford - Photoshop needs some horsepower to crunch those pixels! Also remember that its optimised to take advantage of dual processors on MacOSX!
-Its always preferable to have a separate hard drive to use for scratch disk and the faster, the better! Photoshop even warns you about this on first run since version 7. Photoshop will hammer that hard drive and it prefers a nice clean empty drive rather than one thats fragmented to pieces and hardly has any space left! If you have anything less than 5gb/20% of your hard drive space left, its time to backup or upgrade! I personally have an additional separate 80 gig, 7200rpm, 8mb cache hard drive partitioned into 2 - 50 gig for storage of files ready to archive onto did, and 30 gig purely dedicated scratch disk (which is a little excessive!). I format this partition every month or so to ensure best possible performance - and it shows! Hard drives are very cheap now and you really do get a significant performance increase if you use a dedicated scratch disk.
-The minimum RAM you want installed is 512mb for basic Photoshop work, as both MacOS and Windows XP can soak up 100mb+ before you have even started Photoshop! This would be fine for fairly simple work, and fairly acceptable for a web developer as they work at lower resolutions.
-If you are working on high resolution or multi-layered images destined for print, the minimum you should have installed is 1024mb, if you can afford more - sell your possessions and buy it! Buy the biggest capacity chips you can afford too - you should get the highest capacity chips your system can take - G4 towers (Mirror Door) can take 512mb sticks (4 slots) and G5 towers can take 1024mb sticks (8 slots). Dont fill your precious RAM slots with smaller capacity chips as you will soon fill them all up and will have not realised the full potential of your system. Its always better to slowly upgrade with larger capacity chips, spend that bit extra to super size and you will be a very happy Photoshop Ninja!
Using Photoshop
-Monitor your memory usage in one of two ways - click on the bottom of your image where it shows various information. You can either select ‘Efficiency’ or ‘Scratch Disk’. Efficiency is shown as a percentage figure, if that goes below 100%, you have run out of RAM - simple! The other choice, Scratch Disk, is my preferred one. It shows two figures with a slash in-between them. The figure to the right shows RAM available, the figure to the left shows how much is in use by Photoshop. If the figure to the right is higher, you have run out of RAM!
-The History palette is a fantastic feature, but it eats up memory fast! Set it to the level appropriate for your work. If you have loads of RAM and your working on a low res website visual, you can afford to set it a lot higher. For very high resolution work keep it very low.
- Close down all other running applications before starting Photoshop if you can - I know this is not always appropriate, but they steal valuable memory and processing cycles!
- Ensure you have the maximum system memory allocated to Photoshop, this setting in your preferences makes a big difference and when you are working on large complex images you really should only be running Photoshop. Dont be scared to put this right upto 100%!
-If you have run out of RAM you can purge Photoshops memory (Edit-Purge). However, if you are really way over and youve ripped the scratch disk to shreds this can take quite a while to perform whilst it clears everything out of memory. Dont be worried by satans spinning beachball on OSX, it almost certainly hasnt crashed! Sometimes its just as quick (and more safe) to save your file, quit and restart Photoshop - it does the same thing and sometimes frees up more memory!
Photoshop memory setting revision
It seems that there are mixed opinions on the best Photoshop memory setting - I have said above that it is best to put this at 100%, but it seems that it is best to set this around the 85% mark to give the operating system a bit more memory to use. This does make sense, but I’m keeping mine on 100% personally as it doesn’t seem to slow my Mac down! Experiment and see what seems best for you.