1333 in 1066 slots - reads as 1066 in system report

[sonofsnak]

This could well be my ignorance, but I recently upgraded my Early 2009 Mac Pro 4,1 2.66 Quad Core to 5,1 3.46 6 Core. Upgrade went perfectly. Had only 12GB of 1066 Memory in 3 slots (3x4), replaced with 32GB of 1333 in 4 slots (4x8) (OWC said this would be fine). Seems to run fine, but bus speed still shows as 1066.
Did some Googling and couldn't quite get clarification on why this was happening.

 

[ActionableMango]

NVRAM or SMC reset should fix it. I can't remember which one holds the memory information, SMC I think, but might as well do both.

 

[sonofsnak]

Thanks! Wasn't sure if it was part of the problem.

 

[J&JPolangin]

Did it work, is it showing properly now?

 

[flehman]

NVRAM or SMC reset should fix it. I can't remember which one holds the memory information, SMC I think, but might as well do both.

Yep. I remember after flashing my 4,1 to a 5,1 about a year ago the 3.46 CPU was recognized immediately but the RAM was stuck at 1066. Can't recall which fixed it, but I do remember resetting PRAM, NVRAM, SMC, and several restarts and it finally showed as 1333.

 

[ActionableMango]

By the way, to be sure the NVRAM reset worked, you should hear TWO Apple boot chimes, not one. If you only hear one as normal, you haven't reset the NVRAM.

 

[sonofsnak]

It's the NVRAM reset that fixes it. One boot chime per cycle for me, but I waited for 3 cycles before letting go the keys. The cycles were almost close to a minute apart on mine, BTW.

 

[ActionableMango]

Hmm, that's weird. I wonder if I am remembering it wrong. Well, glad it worked.