Does pc3-10600R 1333mhz work in 2009 Mac Pro?

[Sg335man]

Unfortunately I don’t know sorry it’s way over my head. I await a reply from the seller that the chips are DDR3 1333MHz. It could be he has sent 1066Mhz which would be ok for 4,1 identifier. Or it’s the CPUs that’s causing the system to only work at 1066mhz. I have a feeling that’s the case. I then will have to upgrade the CPUs

 

[h9826790]

Good to know, thanks. Will 1.35V 'PC3L' sticks work? or is it recommended to go with 1.5V 'PC3' ones?

Yes, all 1.35V DDR3 DIMM has backward compatibility on a 1.5V system.