Apple OSes and IDE DMA Support?

KFox wishes to get to the core of this particular issue: "I just recently purchased an iBook and I have noticed that even in Jaguar, the system gets choppy from disk I/O. It appears that Mac OS 9 and Mac OS X don't support DMA access for hard drives, even if the drives are initialized in a UDMA mode. Wintel has had support in this area for a long time (since Win95b). Has anyone in the Mac world had any experience with DMA support on hard drives? Is it supported on iBooks? If so, which models?"

Comments

Re:Choppy Disk or VM switching out

[Golias]

I thought the same thing as the AC when I saw this post. This sounds like more like a VM issue than a "lack of DMA" issue.

I also recently bought an iBook, and the very first thing I did, before I even booted it up, was drop in a bunch more RAM (and my Airport card, while I was in there). I have not experienced the kind of sluggishness you are talking about during disk reads, so that might be what your actual problem is.

OS X is the best OS experience I've ever had, but it is a memory pig. If you have the default RAM in your iBook (probably 128), you are hitting the VM a lot. It's fine if you don't mind a little sluggishness, but memory is cheap now days, so buying more is money well spent. Even another 128 can make a world of difference.