According to the 3660 specs listed here, the supported memory matrix is either 4 x 8GB or 2 x 16GB to achieve 32GB total of RAM.

Thank you!

Memory configurations supported

● 8 GB, 1 x 8 GB, DDR5, 4400 MHz, non-ECC
● 16 GB, 2 x 8 GB, DDR5, 4400 MHz, non-ECC, dual-channel
● 32 GB, 2 x 16 GB, DDR5, 4400 MHz, non-ECC, dualchannel
● 64 GB, 2 x 32 GB, DDR5, 4400 MHz, non-ECC, dualchannel
Specifications of Precision 3660 Tower 13
Table 5. Memory specifications (continued)
Description Values
● 32 GB, 4 x 8 GB, DDR5, 4000 MHz, non-ECC, dualchannel
● 64 GB, 4 x 16 GB, DDR5, 4000 MHz, non-ECC, dualchannel
● 128 GB, 4 x 32 GB, DDR5, 3600 MHz, non-ECC, dualchannel
● 16 GB, 1 x 16 GB, DDR5, 4400 MHz, ECC
● 32 GB, 2 x 16 GB, DDR5, 4400 MHz, ECC, dual-channel
● 64 GB, 2 x 32 GB, DDR5, 4400 MHz, ECC, dual-channel
● 64 GB 4 x 16 GB, DDR5, 4000 MHz, ECC, dual-channel
● 128 GB 4 x 32 GB, DDR5, 3600 MHz, ECC, dual-channel
NOTE: ECC memory is not supported on Intel Core
i3-12100, i3-13100 and i3-13400 processors.

Does this mean that 4 x 8 will work at 4000Mhz, and 2 x 16 will work at 4400Mhz?

Does it say anywhere about memory supported chips...? I am unable to order the same memory modules that are already in use.

@hoba8​ According to the specs that would be correct.