Memory confusion - mine or the machines?

[RAF2000]

This unit came with 2 4gb sticks of RAM, in Dimm1 and Dimm2.  I went over the manual and it says to populate channel "A" (Dimm3 & Dimm4) the same as channel "B" (Dimm1 and Dimm2) for best performance, and to populate black slots first (Dimm1 and Dimm3), then white slots.

So according to that, it should be better to move one stick from Dimm2 to Dimm3.  When I do that, I get the 3 beeps, then 2 beeps, then repeat.

Ok, so maybe I'll bump it up.  I bought two 16gb sticks of what I thought should work, but any configuration involving it gives the 3, then 2, repeat.  I bought DDR4, 1.2v, timing 15-15-15, PC4-17000, Non-ECC, Unbufferred, 288 pin, 2Rx8 Dual Rank..  Not sure why it doesn't like it. No combination of it alone or with the other two works.

But it DOES like the two 4gb sticks it came with, unless I install them how the manual dictates.  Then it doesn't.  Did I misunderstand the manual, or is something just weird?

Any help on the situation would be great, and any insight as to why the new stuff won't work would also be helpful.

Thank you.

Note that the manufacturers website (Timetec) says this memory works in my box.

Update: The new memory does not work in any slot, as before.  However, the old memory that does work in 1 or 2, does NOT WORK in 3 or 4.  Even one stick at a time.  One stick works in Dimm1, or Dimm2, but not in Dimm3 or Dimm4.  I think I need to ship it back and try another...*sigh*

[DGroves]

your system can use either DDR4-2400 (PC4-19200) or DDR4-2133  (PC4-17000) depending on the CPU that is installed higher end cpu's available for this system may support the faster 2400 speed

Maximum memory: 64GB

https://www.crucial.com/compatible-upgrade-for/hp-compaq/hp-prodesk-600-g2-microtower

The system will operate in single channel mode if the DIMM sockets are populated in one channel only.

● The system will operate in a higher-performing dual channel mode if the total memory capacity of the
DIMMs in Channel A is equal to the total memory capacity of the DIMMs in Channel B.

The technology and device width can vary between the channels.

For example, if Channel A is populated with two 1-GB DIMMs and Channel B is populated with one 2-GB DIMM, the system will operate in dual channel mode.

● The system will operate in flex mode if the total memory capacity of the DIMMs in Channel A is not equal
to the total memory capacity of the DIMMs in Channel B. In flex mode, the channel populated with the
least amount of memory describes the total amount of memory assigned to dual channel and the
remainder is assigned to single channel. For optimal speed, the channels should be balanced so that the
largest amount of memory is spread between the two channels.

If one channel will have more memory than the other, the larger amount should be assigned to Channel A.

For example, if you are populating the sockets with one 2-GB DIMM, and three 1-GB DIMMs,

Channel A should be populated with the 2-GB DIMM and one 1-GB DIMM, and Channel B should be populated with the other two 1-GB DIMMs.  With this conƭguration, 4-GB will run as dual channel and 1-GB will run as single channel.

For proper system operation, the DIMMs must be:
● industry-standard 288-pin
● unbuƫered non-ECC PC4-17000 DDR4-2133 MHz-compliant
● 1.2 volt DDR4-SDRAM DIMMs
The DIMMs must also:
● support CAS latency 15 DDR4 2133 MHz (15-15-15 timing)
● contain the mandatory JEDEC SPD information
In addition, the computer supports:
● 512-Mbit, 1-Gbit, and 2-Gbit non-ECC memory technologies
● single-sided and double-sided DIMMs
● DIMMs constructed with x8 and x16 DDR devices; DIMMs constructed with x4 SDRAM are not supported

NOTE: The system will not operate properly if you install unsupported DIMMs.