[Ti] Tom's MacBook Doesn't Always Start

[Kynan Shook]

Actually Jerry, the MacBook has thousands of hardware components, not  
hundreds.  ;-)  All the same, I strongly disagree with your  
assertion; RAM is probably the most complex hardware inside the  
machine, and is typically manufactured to the lowest quality -  
especially if it's not one of the major brands (Samsung, Micron,  
etc.), and sometimes even if it is (Infineon, for example, is one of  
the major ones that I've seen have more problems than normal).
Micron puts it best on their web page (somewhere, at least - I saw  
this years ago); if a RAM manufacturer doesn't catch a fairly large  
number of bad dies in their manufacturing process, they are in a bad  
situation: it means either that they are letting through a large  
number of bad dies, or they aren't manufacturing to the absolute  
limits of technology, and are falling behind every other RAM  
manufacturer.

Furthermore, a lot of the large companies will sell off their  
marginal products (sans the brand name) to smaller companies, which  
will package and sell the broken product.  Discount RAM vendors (like  
1-800-4-Memory) have some of the worst memory out there.  Apple's  
memory will be among the best, but Crucial (crucial.com) is about the  
same quality, for a much more reasonable price.

Having done Mac repair at an AASP, I can tell you bad RAM can cause  
absolutely any problem.  I can also tell you there's no test that  
will catch 100% of bad RAM.  Apple's RAM test tells you as much about  
your RAM as your mechanic would tell you about your car if he glanced  
at the outside of it for 2 seconds; he can tell you if you were in a  
major accident, but if your engine needs a tuneup, he'd never know.   
As far as RAM tests, the AASP I worked at had a $5000 RAM tester that  
worked fairly well, but sometimes, you just had to remove the RAM and  
test the computer without it.  Problems are magnified because bad RAM  
leads to disk corruption, so replacing the RAM sometimes isn't  
enough; the OS and disk directory are corrupted as well.

Tom, I'd recommend (as painful as it is) using one gig at a time.  If  
you still have the original 512, stick that in too so you're only  
down half a gig...  Try it for a couple weeks, then switch the  
DIMMs.  You can try Apple Hardware Test (which came on the install  
DVD with your computer), or giving it to either the manufacturer or  
Apple to test, but they're likely to use AHT, Apple Service  
Diagnostics, or some other software tool to verify the memory.  In my  
experience, these software tests catch at best about 5% of all bad  
RAM.  If they have a hardware tester (ie RAM is physically removed  
and placed in a system designed entirely for testing RAM), I'd have  
better confidence; maybe 75% if it says your RAM is good.  In either  
case, if it says your RAM is bad, I have 100% confidence that it's  
right.


Kynan Shook
kashook at wisc.edu
http://homepage.mac.com/kynan/


Jerry Krinock <jerry at ieee.org> writes:
> on 06/10/22 23:41, T.L. Miller at tlmiller at mac.com wrote:
>
>> I'm thinking that the two gigs of RAM I installed could be the  
>> problem.
>
> Why? Your MacBook has hundreds of hardware components in it which  
> could
> cause this problem, not to mention software.  If it were RAM, I  
> would expect
> to see many different problems; random freezes and crashes at  
> unpredictable
> times, not a single specific problem as you have described.
>
>> Again, any easy way to test RAM? Would an Apple store have RAM  
>> test equipment?
>
> Your RAM is probably tested every time your machine boots.