Bad RAM, Mismatched DIMMs, and Loose Screws, oh my!
Alright, so I have an original (Rev A, I believe - ordered it in September of '03) Dual 2GHz PowerMac G5.
The short version: Apple replaced their defective RAM with the wrong kind, so now I have a DDR333 DIMM paired with a DDR400 DIMM, the DDR400 being the original RAM. I see this as potentially hazardous. Am I right? Also, a screw fell out: http://evula.org/madfax7/misc/images/g5loosescrew.jpg
The long version:
My G5 came with 2x256MB Apple DIMMs, and I later upgraded it with 2x512MB DIMMs from crucial. Now, maybe 6 months to a year after I got my computer, my drive got corrupted. I got kernel panics, crashing apps (particularly WoW, upon entering Stormwind), and general weirdness. I reformated the drive and reinstalled. I ran Apple Hardware Test twice and it came out with a logic board error on the CPU bay fan the second time. I re-seated the fan and tried AHT again, no errors, and all was well, or so I thought.
Long story short, my drive kept corrupting itself every few months. I ran AHT about a bunch of times after I had read that it sometimes didn't catch things the first time around. After maybe the 5th time it caught an error in the Apple supplied RAM. I tried both brands of RAM with out the other in different sets of slots to make sure which was bad. It was always the Apple supplied RAM. Confident I had identified the problem, I took out the Apple RAM. It's been running fine since.
Sort of. A month or so ago one of my storage partitions corrupted itself, but I fixed the problem with a reformat of the disk. This prompted me to start thinking about the bad RAM that needed replacing. Last week my life finally calmed down enough that I could actually get something done about it, so I took my defective RAM into the local Apple store and the technician at the Genius Bar told me I had to bring the computer in so they could make sure it wasn't the logic board or something. Mean while he places an order for the RAM. So I back up my data and yesterday I finally take my computer in.
When I come back, I tell another technician my story. He installs the defective Apple RAM and takes out the crucial (wasn't sure if I was supposed to do that or not), runs a hardware test, and discovers the does indeed result in an error. I mention that the other technician ordered RAM and he goes back and looks for it. Upon opening the box it's discovered only a single DIMM was ordered. "Fortunately", it turned out only one of the original DIMMs was defective. So he takes out the defective one, installs the new one, and runs the test again. All green lights. So I take the computer home.
Once home, I use it for a while. Didn't notice any boot speed difference, which I didn't expect to. Loging in was noticably slower. It used to take 20 or so seconds, now it takes about 30. I would think if anything it would be faster, as all RAM checks are done during start up if I'm not mistaken? I do have about 10 log-in items. Big whoop. Anyways, I've notice the whole system seems marginally slower. Not much, but just a tad. Definitely not as fast as I remember when I was running both pairs back before the Apple supplied RAM died (though that may just be because it's been a while since I've re-installed OS X). But also slightly slower than before I had the RAM "fixed". I decided to run AHT again, and all is green after a quick test and two extended tests. But I notice something odd in the memory overview. I have 4 DIMMs installed, and 3 of them are PC3200, but one is PC2700! I think at first this is probably the oldest RAM, but that didn't make sense as I knew my two crucial DIMMs were the ones verified at the time by crucial for the PowerMac G5 DP. I look at the repair slip given to me, and low and behold: DDR333.
So now I have a mismatched DDR333 DIMM and DDR400 DIMM pair. But, it does run. I thought if the RAM wasn't paired perfectly it simply wouldn't run? Other than the slowness, there don't seem to be any problems. However, this is NOT supported as a practice in the user manual, as it states that PC3200 must be used in my model PowerMac G5. I feel I've been gipped out of DDR400 that I paid for when I bought the computer, and also worried that it's going to cause issues in the future. So my main question is: could this cause problems, and should Apple give me proper DDR400?
When I was first researching about RAM for my computer, I thought it had to be specifically paired to each other (as in manufactured in sequence), but upon researching it now it seems to merely mean the same number of modules and specs. Any thoughts?
Last thing about the RAM, after researching a bit, I read something about the RAM in G5s being 128-bit, and if the RAM was not paired properly it would cause the entire memory system to fall back into a 64-bit mode and as such decrease the throughput. Or something to that effect. However I cannot locate this article now. Is this true? Could this be the cause of my perceived slow-down? Does anyone know the article I'm talking about?
Now, as for the loose screws... When I lifted the computer onto the counter at the Apple store, I noticed a rattle. However, when the technician moved the computer there was no such noise so I assumed I had hit something or it was my imagination. Upon lifting the computer from it's box when I got home though, the rattle was back. It sounded like something rolling around under the motherboard and/or power supply. I removed the door and air deflector and shifted the thing around a bit, and eventually a screw fell out. I've identified it as the same type of screw used to hold the case together (Picture: http://evula.org/madfax7/misc/images/g5loosescrew.jpg ) but I cannot see any empty holes.
One last thing... I bought a WD74GB Raptor to back up my data. xlr8yourmac had good reviews of the drive and compatibility and reliability seemed favorable. So a no brainer I figured, I ordered one from New Egg along with a $30 mail-in rebate. However, when I was backing up I noticed something odd: Big files copied pretty fast, but not as fast as on the pre-installed Maxtor. Lots of little files took exceedingly long amounts of time to copy, however. I ran Xbench on both drives and the Raptor was actually faster in reading and writing 256K blocks, however it was barely a tenth the speed of the Maxtor in reading and writing 4K blocks. Did I get a lemon?
As of this moment I cannot do anything about the Raptor being bad, but I'd be interested to hear if any has heard of anything like it.
I'm going to take the computer back in in the morning and tell them the whole deal, but I was wondering if anyone had any suggestions and could give me some more info on RAM pairings, etc.
Thanks for your patience in reading all this! ;-)
The short version: Apple replaced their defective RAM with the wrong kind, so now I have a DDR333 DIMM paired with a DDR400 DIMM, the DDR400 being the original RAM. I see this as potentially hazardous. Am I right? Also, a screw fell out: http://evula.org/madfax7/misc/images/g5loosescrew.jpg
The long version:
My G5 came with 2x256MB Apple DIMMs, and I later upgraded it with 2x512MB DIMMs from crucial. Now, maybe 6 months to a year after I got my computer, my drive got corrupted. I got kernel panics, crashing apps (particularly WoW, upon entering Stormwind), and general weirdness. I reformated the drive and reinstalled. I ran Apple Hardware Test twice and it came out with a logic board error on the CPU bay fan the second time. I re-seated the fan and tried AHT again, no errors, and all was well, or so I thought.
Long story short, my drive kept corrupting itself every few months. I ran AHT about a bunch of times after I had read that it sometimes didn't catch things the first time around. After maybe the 5th time it caught an error in the Apple supplied RAM. I tried both brands of RAM with out the other in different sets of slots to make sure which was bad. It was always the Apple supplied RAM. Confident I had identified the problem, I took out the Apple RAM. It's been running fine since.
Sort of. A month or so ago one of my storage partitions corrupted itself, but I fixed the problem with a reformat of the disk. This prompted me to start thinking about the bad RAM that needed replacing. Last week my life finally calmed down enough that I could actually get something done about it, so I took my defective RAM into the local Apple store and the technician at the Genius Bar told me I had to bring the computer in so they could make sure it wasn't the logic board or something. Mean while he places an order for the RAM. So I back up my data and yesterday I finally take my computer in.
When I come back, I tell another technician my story. He installs the defective Apple RAM and takes out the crucial (wasn't sure if I was supposed to do that or not), runs a hardware test, and discovers the does indeed result in an error. I mention that the other technician ordered RAM and he goes back and looks for it. Upon opening the box it's discovered only a single DIMM was ordered. "Fortunately", it turned out only one of the original DIMMs was defective. So he takes out the defective one, installs the new one, and runs the test again. All green lights. So I take the computer home.
Once home, I use it for a while. Didn't notice any boot speed difference, which I didn't expect to. Loging in was noticably slower. It used to take 20 or so seconds, now it takes about 30. I would think if anything it would be faster, as all RAM checks are done during start up if I'm not mistaken? I do have about 10 log-in items. Big whoop. Anyways, I've notice the whole system seems marginally slower. Not much, but just a tad. Definitely not as fast as I remember when I was running both pairs back before the Apple supplied RAM died (though that may just be because it's been a while since I've re-installed OS X). But also slightly slower than before I had the RAM "fixed". I decided to run AHT again, and all is green after a quick test and two extended tests. But I notice something odd in the memory overview. I have 4 DIMMs installed, and 3 of them are PC3200, but one is PC2700! I think at first this is probably the oldest RAM, but that didn't make sense as I knew my two crucial DIMMs were the ones verified at the time by crucial for the PowerMac G5 DP. I look at the repair slip given to me, and low and behold: DDR333.
So now I have a mismatched DDR333 DIMM and DDR400 DIMM pair. But, it does run. I thought if the RAM wasn't paired perfectly it simply wouldn't run? Other than the slowness, there don't seem to be any problems. However, this is NOT supported as a practice in the user manual, as it states that PC3200 must be used in my model PowerMac G5. I feel I've been gipped out of DDR400 that I paid for when I bought the computer, and also worried that it's going to cause issues in the future. So my main question is: could this cause problems, and should Apple give me proper DDR400?
When I was first researching about RAM for my computer, I thought it had to be specifically paired to each other (as in manufactured in sequence), but upon researching it now it seems to merely mean the same number of modules and specs. Any thoughts?
Last thing about the RAM, after researching a bit, I read something about the RAM in G5s being 128-bit, and if the RAM was not paired properly it would cause the entire memory system to fall back into a 64-bit mode and as such decrease the throughput. Or something to that effect. However I cannot locate this article now. Is this true? Could this be the cause of my perceived slow-down? Does anyone know the article I'm talking about?
Now, as for the loose screws... When I lifted the computer onto the counter at the Apple store, I noticed a rattle. However, when the technician moved the computer there was no such noise so I assumed I had hit something or it was my imagination. Upon lifting the computer from it's box when I got home though, the rattle was back. It sounded like something rolling around under the motherboard and/or power supply. I removed the door and air deflector and shifted the thing around a bit, and eventually a screw fell out. I've identified it as the same type of screw used to hold the case together (Picture: http://evula.org/madfax7/misc/images/g5loosescrew.jpg ) but I cannot see any empty holes.
One last thing... I bought a WD74GB Raptor to back up my data. xlr8yourmac had good reviews of the drive and compatibility and reliability seemed favorable. So a no brainer I figured, I ordered one from New Egg along with a $30 mail-in rebate. However, when I was backing up I noticed something odd: Big files copied pretty fast, but not as fast as on the pre-installed Maxtor. Lots of little files took exceedingly long amounts of time to copy, however. I ran Xbench on both drives and the Raptor was actually faster in reading and writing 256K blocks, however it was barely a tenth the speed of the Maxtor in reading and writing 4K blocks. Did I get a lemon?
As of this moment I cannot do anything about the Raptor being bad, but I'd be interested to hear if any has heard of anything like it.
I'm going to take the computer back in in the morning and tell them the whole deal, but I was wondering if anyone had any suggestions and could give me some more info on RAM pairings, etc.
Thanks for your patience in reading all this! ;-)