I have an HP Compaq 6000 Pro Small Form Factor PC need help with ram

[smael]

i have bought a 4gb ram stick but i already had 2 2gb ones

what order should i keep them at the red light 5 beep keeps coming 

[DGroves]

these systems are extermly picky on ram, you really do need to use only recomended ram modules or you may have random memory related issues

On your system populate dimm modules

DIMM1 socket, Channel A (populate first) Black   (2gb dimm)

DIMM3 socket, Channel B (populate second) White (2gb dimm)

DIMM2 socket, Channel A (populate third)

DIMM4 socket, Channel B (populate fourth)

the dimm sockets are numbered with dimm 1 closest to the CPU cooler

and dimm 4 is farthest from cpu cooler

The motherboard does not support 8GB dimms per stick. Use four 4GB sticks to achieve 16GB. which is the max ram this board can handle

The system will automatically operate in single channel mode, dual channel mode, or flex mode,
depending on how the DIMMs are installed.

● 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 512-MB DIMMs and Channel B is populated with one 1-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 1-GB DIMM, and three 512-MB DIMMs,

Channel A should be populated with the 1-GB DIMM and one 512-MB DIMM, and Channel B should
be populated with the two 512-MB DIMMs.

With this configuration, 2-GB will run as dual channel and 512-MB will run as single channel.

● In any mode, the maximum operational speed is determined by the slowest DIMM in the system

http://h10032.www1.hp.com/ctg/Manual/c01870887

both corsair and kingston have web sites where you can select memory that is guarenteed to work

https://www.crucial.com/upgrades

https://www.kingston.com/en/memory