Don't mix ECC and non-ECC in that Dell.

No. You cannot mix ECC and non-ECC RAM in a Dell T1700 — or almost any workstation that supports both types. The motherboard either expects one or the other, and mixing them usually results in no boot, random crashes, or the system treating all sticks as non-ECC anyway (if it even posts).

The T1700 is picky. It supports ECC memory, but only if you populate all slots with ECC sticks. The memory controller is integrated into the CPU (Haswell or similar), and it’s not designed to handle a mix — the signaling and error-correction logic are incompatible.

If you need 16GB total, buy two matching 8GB ECC sticks (they’re cheap used) or two matching non-ECC sticks. Selling or trading the mismatched stick will cost you less time than fighting with a machine that won’t boot.