RE: Precision T3500 Processor Upgrade
I'm running 24GB in my T3500 machine. I wouldn't try anything more than the recommended. If you need more memory capability, pick up a used T5500. It is capable of 72GB & Dual Processors (5500 & 5600 series).
Part Numbers I've found for the T3500 memory.
Dell P/N - SNPT192HC/4G
Hynix - HMT351U7AFR8C-H9 T0 AB
Samsung - M391B5273BH0-CH9