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The info I could find from Apple about this, helps nothing and Apple Brazil doesn't sell memory (despite being at least 3x more expensive than regular Apple) so I don't know how to buy official modules.

Couple days ago I bought 2x2GB (Kingston DDR3 1333 CL9) for my macbook pro, and I think it may be bad quality.

I ran Rember (memtest) with 5 loops for almost 3 hours and it brought no errors! But I keep getting random system crashes (which never happened before) and I can't run Steam's Trine without something breaking (app crash, computer freeze, etc). I even made a guide (initially to myself) on how to recover from crash from what I've learned, since I knew nothing about it before.

Actually, after running Rember, my computer haven't freezed yet and for the first time Steam's Trine began to crash rather than freeze the system. Regardless of this, I think the questions are relevant.

edit: Yep, I put back old memory, and no crashes anymore plus Trine runs just fine. I've actually tried fixing Trine before changing memory, but it didn't help. Anyway, I still don't know if the problem is the brand, ECC, timing, clock or any combination of them!

4 questions:

  • How can I assure my problem is from the memory (other than trial and error)?
  • Is there a way to activate its ECC? System Profile says it's disabled.
  • Maybe there's some procedure on OSX after installing new memory... is there any?
  • If I go to buy a new memory (after returning this one), I want it to work. What should I look for and how could I perform some stress test on it before acquiring? I don't plan on running Rember and waiting at least 30 minutes on the balcony.

last edit: Crucial website rocks for identifying best modules for your mac, after all. But they don't provide all options. 1gb 1067 + 4gb 1333 is a very good option, depending on your future upgrading plans. I ended up buying 2x 2gb 1067 PC8500, for really cheap, and that just worked. More details on apple forums.

Meanwhile, answering my own stupid questions:

  • I believe there's no simple way to assure where the crash originated (memory, software fault, whatever)
  • I also guess there's no way to "activate" ECC, plus ECC memory still is always much more expensive. What I now know for sure is that my mac pro doesn't support ECC.
  • There's no special procedure after installing new memory on the mac.
  • Just running Trine worked as a perfect way for trying out the new memory.
share|improve this question
Your memory needs to be the same type, including speed and timing, as the RAM in the machine. We've done upgrades with Kingston and they've been fine. – user3463 Dec 1 '10 at 18:23
@Randolph that's really good to know. So, higher speed (mine is 1333, advised on apple is 1066) is also bad? how can I tell the timing from the previous RAM? And I know nothing about timing, I'll have to research that... – cregox Dec 1 '10 at 18:58
Here's an old article explaining RAM timings. What you need to find out is what is in the box first. – user3463 Dec 1 '10 at 19:57
@Randolph and here's a new link on CL issues with mac: - from your link's reading, seems to me lower the CL (timing) is the faster and it's actually independent from other memories bank. Plus people do use different speeds and timing with no bigger issues, seems like. Which means my case is still a mystery and I'll have to keep on trial and error for now – cregox Dec 5 '10 at 3:17
up vote 1 down vote accepted

You could try another memory type. I've always bought crucial memory for upgrading our Macbook Pro's and Minis and we've never had any problems.

You can't really test the memory before hand, you just have to get it and try it out.

The other thing to double check is that you have the right memory speed. See if you can figure out what speed your computer currently has and buy the same.

share|improve this answer
memory type or brand? does the speed have to be exactly same? in the old days, higher speed wouldn't be an issue (which is my case). – cregox Dec 1 '10 at 18:59
Higher speed shouldn't be a issue. But Macs don't really let you control the hardware quite like other computers do, so I wouldn't be surprised if it got caught up on it. But you are right that it should work. I would try to use crucial and see if that works for you. Like I said I've used them in Mac Minis and Macbook Pros (among other things). – Nori Dec 1 '10 at 20:30
Mac don't let we configure BIOS or whatever, but does it configure it automatically? can a memory with wrong clock settings even run at all? if the mac does auto-configuration, does the memory need to have some module to allow it? I really think if I buy crucial of same setup it won't help... last thing, I should just go with ignorance crowd and look for some vendor with mac expertise. that sums it up. – cregox Dec 2 '10 at 13:25
I second the recommendation for Crucial. In the unlikely event that you get a bad stick, the returns procedure is simple and there's a minimum of fuss in getting a replacement (although I've only had to use it once). In addition, their website makes it really easy to pick the right type of RAM. I don't know what your options are for ordering in Brazil, though - I doubt you'll get the same East Kilbride boys and girls I get in Scotland. They do have a US store, but I've no idea what exporting computer parts is like. – Scott Dec 2 '10 at 13:48
Yeah Macs don't allow any config. So just try to get the same speed. Like Scott said, Crucial's website makes selection pretty easy so check that out. Like I said I've used Crucial on many Macs with no problems what so ever and I used their memory finder too. – Nori Dec 3 '10 at 14:50

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