the only thing we dont have (yet) is an ssd. everything else should be fine. and again, i am trying this on a very simple example. comp with one layer which is just a clip.

deactivating this is not really an option as this was the primary reason we switched to cs6.

i doubt this will work that much faster with an ssd.

anybody from the developers around to comment on this?

sorry, my bad

so the machine is a dell precision t7500, 2xquad xeon, 24gb ram, quadro fx 3800. it has a system drive plus a data drive. both are sata drives (i think they are both wd raptors). both drives have around 140 MB/s read/write performance (thats what the atto benchmark tells me).

there is a similar system here with 2x six core xeons, 24 gb ram, quadro fx 4000. rest is the same. the system has the same issues with disk cache.

there is a server, which delivers all source images which reads/writes at around 120 MB/s.

our test was taking hd footage from the server (tif sequence, 8 bit) and putting it into a comp. no fx. ram preview --> about 5 sec. of footage are done in a couple of seconds.

data disk with the diskcacge folder starts to make noise(writes). writes a couple of minutes.

so we purged everything, deleted all the diskcache and did a background render diskcache for the comp. same thing here. writes a couple of minutes which takes the the ram preview only seconds.

checked the cache files. they are just 8 MB a frame and there seems to be the right amount of cache frame (for 5 sec. of footage)

is there anything special about how ae cs6 writes the cache files - like doing it in tiny blocks or so?

we have no problem getting some ssd drives, but we want to make sure, that it works as advertised.

diskcache goes on data drive - forgot to mention.

btw. once the cache is written, reading it back into ram is superfast.

i doubt that. the same problem occures if i take a solid, apply a fast blur with some keyframes (there is no i/o to render that) and create the cache. writing cacheframes is just slow. normal rendering is fine (even to the networkdrive).

we dont cache to the networkdrive!

hmm, so you are telling me you are not having those issues with diskcach? would that be something, a paid support case could solve?

so we did a couple more tests and figured out, that the write performance of our drives for smaller blocksizes is pretty weak (allthough the drives are fast in general). this is true for pretty much all the machines we checked (around four). so it seems, aftereffect does write the cache files in chunks smaller than 128 kb (probalby even smaller), which causes the bottleneck for us - every file is more than 8 MB in size.

funny sidenote: we did a test, writing the diskcache onto the server which seems to be a lot quicker with writing small junks and the performance is a lot better, almost as expected!

so we just ordered an intel ssd to see how much this changes the performance. I'll keep you posted about that (will take a couple of days).

btw. did you do your tests with an ssd drive?

ps: i knew some of the presentations for the diskcache features, thats why we figured out that something was wrong. thanks for pointing me at the video though.

Hi Rick,

here are some updates to our situation with the diskcache:

we got ourselves an intel ssd and plugged it in one of our systems. the atto benchmark show much higher throughput with small blocksizes but in AE the situation has not changed. its as slow as before.

Is there a chance that you or anybody who is reading this could do a test on a windows7 machine?

the last thing we could try is to get an ssd pci card which is not connected to the sata-port of the machine.

thanks,

Ronny

Hi Rick,

so we got ourselves an ultrafast internal pci ssd card (read/write about 1.4 GB/sec) and now everything works as expected (actually even better - aftereffects is pretty much realtime now).

still the problem remains, that with everything that was connected to the sata controller of our machines, the performance was really bad. we talked to our system administrator about the issue, but he wouldn't know of anything that could fix the problem.

my guess would be, that it is a very specific problem with the combination of dell workstations (and their sata controller) and the way aftereffects writes the diskcache. is there any way to bring this to the attention of the developers, because i'm sure (and i have already read on other forums) that other people are having this issue and its certainly not an option for everyone to just plug an ssd card into their machines (though it's really sweet :-).

So this issue is not fixed, we just got ourselves a pretty expensive workaround.

Anyways, thanks for your help and your patience.

cheers,

Ronny