Apple only supported 4GB FB-DIMMs in these models, for a total of 32GB RAM.
However, the chipset was always suspected to support 64GB with 8GB FB-DIMMs, but everyone who tried this only had RAM recognized up to 32GB RAM.
But today there's an interesting post on netkas of someone who used mostly 8GB FB-DIMMs and left two 4GB FB-DIMMs in the last two spots of the second riser.
The apparent result? 56GB RAM in a MacPro2,1
Very interesting if it really works properly.
However, the chipset was always suspected to support 64GB with 8GB FB-DIMMs, but everyone who tried this only had RAM recognized up to 32GB RAM.
But today there's an interesting post on netkas of someone who used mostly 8GB FB-DIMMs and left two 4GB FB-DIMMs in the last two spots of the second riser.
The apparent result? 56GB RAM in a MacPro2,1
Very interesting if it really works properly.