Thank you for purchasing through links and ads on this site.
OWC / MacSales.com...
diglloyd Deal Finder...
Buy other stuff at Amazon.com...
Capacities up to 48TB and speeds up to 1527MB/s

Beware of Memory Usage and Mac OS X Cache

Last updated 2011-02-10 - Send Feedback
Related: software, Software, Photoshop
Example: Mac Pro with 24GB
Use 70% at most on any Mac!

Photoshop CS5 allows you to limit the memory it uses, in percentage terms, as shown at right for a Mac Pro with 48GB memory*.

It turns out that Apple introduced a nasty little performance bug 6-10 months ago in Mac OS X 10.6, such that the unified buffer cache used by the file system is now swappable, meaning that it will be paged by the virtual memory system to disk.

This nasty little Apple bug means that if you let Photoshop CS5 use more than about 70% of physical memory, you’ll seriously degrade your performance if CS5 actually tries to use that much memory (if usage actually stays below 70%, your Good).

* CS5 does its math wrong in the Memory Usage dialog, 24GB should be 24 * 1024 = 24576 GB available. Also, the displayed figures are just plain silly, there’s no reason not to round them to the nearest 10MB. Finally, setting a value and coming to the dialog again shows a different number! Someone asleep at the wheel on this dialog.

Up to 1527MB/s sustained performance

Testing using diglloydHuge

I used the diglloydHuge benchmark to test a large-file scenario which needs about 56GB of memory to run at maximum speed.

With enough memory, diglloydHuge should take about 112 seconds on a 3.33GHz Mac Pro. With 24GB memory, the time is greatly increased, but how badly it degrades depends strongly on the maximum memory Photoshop is allowed to use.

Performance with varying memory and “Memory Usage” settings
    
At 70%, no virtual memory paging, but 4.4GB of page-outs when set to 100%

 

 

Durable and fast, up to 1800MB/s
B&H Deal ZoneDeals by Brand/Category/Savings
Deals expire in 4 hours unless noted. Certain deals may last longer.
$1199 SAVE $500 = 29.0% $19 FREE ITEMS Canon 18x50 IS Image Stabilized Binocular in All Other Categories
$1049 SAVE $450 = 30.0% $20 FREE ITEMS Canon EOS 77D DSLR with 18-135mm USM in Cameras: DSLR
$1697 SAVE $300 = 15.0% Nikon D750 DSLR in Cameras: DSLR
$2797 SAVE $200 = 6.0% Nikon D810 DSLR in Cameras: DSLR
$898 SAVE $100 = 10.0% Sony DSC-RX100 V in Cameras: Point and Shoot
$300 SAVE $160 = 34.0% $9 FREE ITEMS Steiner 8x32 XC Binocular in All Other Categories
$1099 SAVE $200 = 15.0% ZEISS 25mm f/2 Batis in Lenses: Mirrorless
$1299 SAVE $200 = 13.0% ZEISS 21mm f/2.8 Loxia in Lenses: Mirrorless
$1999 SAVE $300 = 13.0% ZEISS 18mm f/2.8 Milvus ZF.2 in Lenses: DSLR

diglloyd.com | Terms of Use | PRIVACY POLICY
Contact | About Lloyd Chambers | Consulting | Photo Tours
Mailing Lists | RSS Feeds | Twitter
Copyright © 2008-2017 diglloyd Inc, all rights reserved.
Display info: __RETINA_INFO_STATUS__