Prefetch of Clips?

[Piplodocus]

Sometimes I get big glitches and dropouts on sections of songs when new parts come in on my Macbook which didn't used to happen on my old Hackintosh. Any ideas why?

My old Hackintosh had OSX/Ableton on one 7200rpm drive, and my library/samples/songs on a second 7200rpm drive, and it was a 3GHz Core 2 Duo with 800MHz FSB and 4GB RAM. The new Macbook Pro is a 2.66GHz i7 with 4GB 1066MHz memory, with OSX/Ableton on a 7200rpm Seagate Momentus XT (hybrid - with latest firmware), with Library/Samples/Songs on a 2nd 7200rpm Hitachi (in an optibay). Therefore it should be just as fast, if not faster! Any ideas?

I was wondering (on a completely related note) does Ableton prefetch the beginning of all clips as well as things loaded into sampler/simpler? How long is the prefetched bit? I don't want to load all of the long samples into RAM obviously.

Also if I have a Session Drums kit will the prefetch be long enough to load all of the drums samples? If not is there a way to load a complete kit into RAM without going through the hundreds of clips in all of the different samplers that make it up, and putting them all into RAM individualy as that'd take AGES to do!!!! When running it seems to have a good 700MB+ of RAM "spare" in the activity monitor.

[Ableton_David]

Hi, please contact Ableton Technical Support about your issue: http://www.ableton.com/support. Thank you.

[Piplodocus]

Think I've fixed it!!! Don't buy a Seagate Momentus XT! Just replied to Ableton support as below:

I might have fixed the problem! To early to say as I've been far too busy this weekend, but I made the wedding playlist simple project that runs at only about 4% on the usage meter stop glitching regularly. I'm yet to try my other proper/full projects that use a lot more CPU etc. so can't say it's "solved" but it looks like it may be.

It appeared to be my 500GB Seagate Momentus XT Hybrid drive. Don't know if you know anything about these drives but the principle is it has a standard 500GB 7200rpm platter drive, and also 4GB of flash NAND. It works out which sectors of the drive you're accessing a lot, and copies these into the 4GB of flash storage so regularly accessed sectors are got from the flash memory and hence it should be nearly as fast as an SSD depending what sector you're accessing. However, after investigating lots of forums it appears there are still a few issues even with the latest firmware (SD23), not directly related to disk load. I ended up changing my OSX/Ableton Hard disk to a WD Scorpio Black and now it works! I ran the DJ set I'd had a glitch anywhere between every 3-20mins.

I can therefore confirm that there's a definite issue with these Seagate drives using any firmware up to and including the latest SD23 firmware. As a result I'd circulate this info around Ableton technical support in case anyone puts one of these "faster" drives in their laptop and has the same issue. They do seem generally faster a lot of the time so I'm hoping they'll sort this out with a new firmware version, but they seem to have some kind of problem with continuous sustainability of access. At present I'm going to keep the drive here in case a new firmware comes out soon, then reinstall and retest it. If a firmware update doesn't come soon I'll return it and get my money back.

I'll get back to you if I have problems with my other projects when I get a chance to test them all.