Thanks for the responses. This morning, after having shut down/restarted, things seemed a bit better, but were still far from satisfying. Stating that things are slow doesn’t quite cut it, so I provided some numbers below. That’s mostly to give you an idea of what I’m seeing rather than to be perfectly accurate. Still, although variable, the numbers tend to be close to what I list, as are the patterns in which they occur.
To begin with, loading the file in Safari* fairly consistently takes about 22 sec.
- Zooming (via the zoom button, or with Command+) was instantaneous, but 3-6 sec later the SPOD appeared for 15-20 sec. Clicking anywhere in the window, resizing or repositioning it invariably brought back the SPOD for another 15-20 sec. Sometimes that even happened without doing anything at all with mouse or keyboard.
- Scrolling was abnormal, in the sense that clicking in the scroll bar invariably returned the view to the top (Vert) or the left (Hor), regardless of where in the respective scroll bar I clicked. This was accompanied by at least 10-15 sec of SPODding. If the scroll handles were already at the top or the left, clicking had no effect other than bringing about the SPOD. Dragging the scroll handle worked, but only for a short distance (about half a page worth max), after which dragging was non responsive for about 5 sec.
- The cursor itself behaved abnormally too, often remaining in Insertion bar mode where it should return to arrow or vv.
Preview fared little better, with foibles all its own. The file loads in about 5 sec, but
- SPODs for over 30 sec after hitting the zoom button once. Moving the cursor just a tad brings on another bout of on-off SPODding that may last up to 3 minutes (!). Reducing the window size from max to about half took another 25 sec. The next zoom click took altogether 1 minute before the on-off SPODding stopped. Usually though, clicking on the zoom button produces an instantaneous result, followed after 3 sec by up to 40 sec SPODding, briefly interrupted at 15 and 30-35 sec. Go figure.
- Scrolling was an unadulterated pain too: just clicking the scroll handle often (but not always!) brings up a 15-20 sec SPOD. Dragging it brings another, slightly shorter one, before the window scrolls a few lines. Clicking in the scroll bar works as expected (e.g., one ‘page’ up/down or left/right), but only after 5-10 secs being unresponsive, followed by another 5-30 sec SPOD. And then there is the odd case where there is no delay at all…
All this rarely seems to touch CPU cycle or RAM use, and then only marginally.
Just for giggles, I loaded the file in about 2 sec into Preview 5.0.3 under Snow Leopard (10.6.8) on a 2008 MBP. After a subsequent SPOD of about 25 sec, it zoomed fairly snappily and scrolled at about one line or page per sec. In contrast, Adobe Reader 11.0.11 only showed an empty window. On the iMac under Yosemite, AR DC 15 ‘improved’ upon that by displaying placeholder graphics at all zoom levels. This strongly suggests that there is something non-standard about these files, but even so, to say that I am underwhelmed by the way the then top of the line 2014 iMac handles them doesn’t quite cover my feelings…
*) I turned off extensions and Little Snitch to minimize any delays these might cause.
