that rx 400 card on your ho to me looks unlikely for what I see just a card that requires ''''READ PAGE 2-3, Under SFF models ---
that sets your limitations (Low Profile, Maximum 25 watts in PCIe Graphics x16 slot).'' ?
that's between you and HP and anything you do over what they speced and sold the computer for is ''ALL YOUR OWN RISK''
youi risk and buy the card and it works , well no harm . you buy the card and it done for any reason , well you out the money on the card if you cant return it for a refund
that's all there is to it .. so with whats said there it seems to be a 25w slot on that motherboard and then you put a card in that needs 75w ?? do you expect it to work ?
all you can do now is what YOU feel is best and hope for the best . all I can do is point out with a porebuilt things are not so plug and play as your lead to believe
the rest is up to you to look up and research
like look here under graphics cards
http://h20564.www2.hp.com/hpsc/doc/public/display?docId=emr_na-c02742852
then look art one in the list
[NVidia is easy to look up]
http://www.nvidia.com/object/product_quadro_nvs_295_us.html
then in the spesc of that card
Maximum Power Consumption 23w
so hp limits the slot power to that 25w and limits you to these type of cards [ HP- PROPRITORY ] motherboard
then if you look here seems HP used 4 different mother board ?
http://h20564.www2.hp.com/hpsc/doc/public/display?docId=c02742792
''For use in 6200 Pro Series models: '' i'll bet these 2 boards have a higher slot power for the use of the AMD 6000 series cards HP put in them [still may not be full 75w pci-e atx standard ] could just be bumped just enugh to use the AMD card in them
anyway ... its all your own risk
your on your own from here