Issues with new iMac mid2013

Hi all,

My machine is the 27", 3.4GHZ i7 with 24gig ram (16gig OWC, 8gig Apple), GTX675.
I believe I am not getting the performance I should out of my new iMac and a friend of mine had similar performance issues plus some weird screen behaviour (which I don't get). We both have a mixture or OWC RAM and apple RAM. He took his iMac to Apple who traced the problem to his OWC. The Australian reseller who is excellent immediately offered to replace his RAM under warranty which he is in the process of doing. He also did a lot of research in the meantime and it appears that the Apple RAM is a higher specified RAM (also much more expensive) than what OWC is offering.

My performance issue is that a pre rendered timeline(37min) took over an hour to export to prores (same flavour as project settings) there are other instances that are subtle but where I would expect better performance.

The Current arrangement of my RAM is I left the two apples 4gig chips in the slots when it was shipped and slipped the OWC into the vacant slots. Is there a better arrangement of slots?

Has anyone else had issues with mixing OWC with Apple ram?

It has been suggested that I remove the OWC ram and see if that improves performance or remove the Apple ram. Has anyone experimented with these options?

Cheers

Ian

I hate to be a Debbie Downer here, but, something doesn't add up.

RAM will not effect the speed of things such as exports and renders. But can effect overall stability.

I've used OWC RAM for a decade now, never had an issue, except for bad RAM once, and they overnight replaced it. I would suspect the Apple store guy's compentence if he claims OWC RAM can make your machine run slower. At least have OWC verify the RAM is bad, at least. Bad RAM can effect things.

OWC RAM is up to Apple specs. Apple has a more strict quality control system, more strict than anyone else in the industry. Which is why they have by far fewer DOA machines than anyone else. But the "specs" are not different, really.

I don't buy that OWC RAM will slow your machine down. Sorry, I have to strongly disagree here. There is something else going on, "if" in fact your machines are not giving full performance.

What external media drives are you guys using?
Are you optimizing media on import?
There is WAY more important things that effect performance "speed" than RAM.

Thanks Ben,

I and my friend use optimised media for everything that needs it. The OWC RAM was tested and found to be faulty as happens occasionally with any manufacturer including Apple. As I mentioned the local OWC has replaced the RAM purely on the basis of Apples test results.

I am thinking we will do some stress tests in FCP ourselves to get to the bottom of the issue, between us we have enough Apple RAM to run purely on that, and compare it with OWC. I will do it on a Mavericks machine rather than under Mountain Lion which I am still running as that will be much more relevant to most of us.

With my friends machine there was no doubt in the Apple Tech's mind that the RAM was causing an observable display issue. But in the case of my Machine your point is quite valid, I have no measurable way of knowing whether my issue is imagined or not and that is why I want to now do some side by side stress testing. This is also why I wrote to the forum, to see if anyone else had issues similar to ours.

I hope that we find absolutely no difference, as the last thing I want to do is pay out $500 plus dollars for Apple RAM.

Cheers

Ian

I would lean on something else being wrong, but a good way to test would be to remove the extra ram like you said and see how long it takes to export. There's no way it would take that long, especially with a pre-rendered timeline. Are you sure it's all rendered, and does it play back fine without stuttering? What are the project settings? One of my machines is the same gen iMac but with the GTX 680MX and it's pretty fast. The 675 is not that much slower.

I did a very quick test on the first 4 percent of the timeline using an iPhone stopwatch. The total length of the timeline was 52 min and 30 secs. Just to clarify, during the render I referred to, the last 2/3 of the time line slowed down which didn't make sense if it had been pre rendered unless of course it ignores the previous render and re renders it all again.

To answer Ben's question re storage-I use a seagate 4 TB thunderbolt raid which gives very good 134Mb/s write and about 140Mb/s read.

The results of 8 gig of apple ram was 1 minute 34.04 seconds.
The results of adding 16 gig of OWC was 1 minute 34.05 seconds.

There is no significant difference between the two results. At the very least we can say that the OWC RAM has no effect. This would support Ben's original statement that RAM is unlikely to be the issue.

Cheers

Ian

Other things to check: are you using compound clips within compound clips and things like that? Is the timeline in a project, or are you using compound clips as sequences? You could also try deleting all the renders in events and projects, and then rerendering just the project you want. It sounds like the reason it might be taking so long is that it's insisting on rerendering 2/3rds of the show for whatever reason.

Hi

I do have a number of compound clips, I know a lot users frown on using them but surely this is one of the great innovations in fcpx and I have not come to grief yet in using them yet however maybe there is a rendering time penalty in using them.

I am going to do more testing over the next few weeks so I will report back in due course.

Cheers

Ian

Don't get me wrong. Compound clips are great and I use them all the time, but I would avoid doing things like putting compound clips inside a compound clip inside a compound clip, for example (extreme nesting).

I actually used to use them like sequences in FCP7, but I found that very complicated compound clips used a lot of memory in an event (because they are stored in events). If you have something like a bunch of 30 minute timelines that are compound clips, it would slow down the system a lot. So now, I mostly use projects as sequences, which is what the programmers intended.