Odd G4 RAM problem

[adcx64]

Hey guys,

My MDD has all four slots on the logic board filled with RAM in this configuration.

PC 3200
PC 3200
PC 2700
PC 2700

I know that the RAM will only run as fast as the slowest chip, but system profiler registers all the ram as PC 2600. I know this Mac supports at least PC 2700. The first RAM slot has one of the little white locking arms broken off. Do you think that would have anything to do with it?

 

[Nameci]

Nope.

 

[adcx64]

What could be causing the reduced speeds?

 

[Nameci]

It is a known bug I guess if you mix RAM speeds...

 

[zen.state]

It is a known bug I guess if you mix RAM speeds...

This. The 133MHz MDDs report 2100 properly but the 167MHz report 2700 as 2600. Been like that on every 167MHz model I have ever used.

 

[ThunderSnake]

Some ram modules report incorrectly. Don't worry about it. Your Geekbench scores looked fine.

 

[zen.state]

What could be causing the reduced speeds?

That clip simply just helps it stay locked down. If the stick is in all the way and you don't pull at it it won't ever come out. The RAM will either work or not. If it works then it works 100%.

Not an issue at all. You may even be able to replace that clip with almost any clip. Even one off a scrap x86 board.

 

[adcx64]

I understand now. Thanks for all the help guys. I knew the clip was only for holding the module in place, but I wasn't sure if the false reading was caused by the ram not being seated correctly.

 

[Nameci]

I have two powermacs MDD FW800, oddly the other one reports PC2600 and the other is PC2700. The one that reports PC2600 is mixed with 2 pairs of same brand each while the PC2700 is 4 sticks of samsung...

 

[adcx64]

Pretty sure all four of my sticks are different brand. Tomorrow I will try just the 3200 or just the 2700 to see what I get.

 

[ThunderSnake]

Tomorrow I will try just the 3200 or just the 2700 to see what I get.

I don't want to dissuade you from conducting some experiments. I think that's a very good way to enhance one's understanding of how things work and I admire your curiosity. Be aware, though, that System Profiler does not actually measure the speed of installed memory. It simply reports what is coded in the EEPROM of each module. There are two things that can go wrong:

1) System Profiler does not always know what to make of mixed modules.

2) If the module does not report information about itself (via EEPROM) in the exact way that System Profile wants to receive this information, it defaults to reporting 2600. Running matched modules will not guarantee that they will show up correctly.

...while the PC2700 is 4 sticks of samsung...

Heh. Same here. My only machine that reports correctly is loaded with matching Samsung modules.

 

[adcx64]

I understand now. I didn't know that about system profiler. One of the sticks is a no-name brand with just "PC-2700 COMPATABLE" printed on the sticker. I bet this is the culprit. All the other sticks are name brand OCZ,Samsung, and Kingston. I am going to try the experiment just out of sheer curiosity, leaving the non name brand stick out. I will look in my parts bin for some name brand RAM ad well.

Thanks a lot. I'll report back with my findings.

 

[WGoins88]

I have 2 1GB sticks of Corsair PC3200 in my MDD, and it reports it as 2600 instead of 2700. I don't see it as a big deal. And they have Samsung branded chips on them.