Decided to max out the ECC RAM in a PowerMac G5 (11,2) dual core 2.0GHz. A few days and eight sticks of RAM later, the G5 boots and reports that 16GB of ECC RAM is installed. However! When I look in the Memory section of System Report, one of the sticks is listed as PC2-3200 instead of PC2-4200.

Details:

• The RAM is all sourced directly from OWC.
• Even though all the RAM was sourced from OWC and has the same SKU, two of the eight 2GB sticks are visually distinct from the others with physically larger chips.
• Those two odd sticks are nearly sequential serial numbers (one ends in 58 and the other ends in 60).
• The RAM chips on those odd sticks appear to all share the same part number (Elpida EDE1108ACBG-6E-E). On the data sheet that pegs them as 128MB DDR2-667 (AKA PC2-5300) parts, which I guess makes them faster than what the G5 can even take advantage of?

I tried moving those two sticks around to outer slots and the same stick continues to report as PC3200. Because G5s use matched pairs I honestly didn’t even know that the computer would boot in this state, let alone report 16GB installed RAM in the "About This Mac" window. Is it just possible that the G5 is misreporting the RAM’s speed?

I’ve reached out to OWC to see if they can find a replacement stick for me but considering that it appears I’ve cleaned them out I’m not sure that’ll happen. Honestly, I doubt there will be anything I could do with this machine that could reasonably push 12GB of RAM anyway but it would’ve been nice to completely max it out.

Anyone have any ideas for how I could troubleshoot this? On OWC’s recommendation I did try rubbing the contacts with an eraser and then cleaning it with isopropyl, but still no dice.