how I know my pci e x16 slot is 75w or lower

no its not on proprietary motherboard like hp and dell like dontlistentome said like dell will print that next to there pci-e slot on the pcb

http://en.community.dell.com/cfs-file/__key/communityserver-discussions-components-files/3515/25WSLOT.jpg

with that your pretty much stuck with a low powered lo pro card like a gt710 @ 19w

but with any prebuilt heres my disclaimer to you

some models of store bought computers [dell.hp,acer,ect..] may come with a ''locked or fixed'' / legacy or uefi bios and may not allow you to change certain hardware as a video card.. this is done to protect them from undue warranty claims and refunds .this is not done to hurt you but to protect them. you really need to see if that upgrade has been proven to work in your model first before you invest money in it .. there are a lot of these threads here at toms to look at some models will allow upgrades and some dont.. and a lot of guys here say ya ya ya when is really no no no...it would be sad you spent $200 on a card that won't post after you installed it as most find out. then get told its your psu and you spend more and end up right back where you are now, but its up to you good luck..


you got to know the boards in these computers are not like the ones we use to do custom builds witch are open to upgrading with in the boards compatibly . the bios is custom made for there design and just for the parts they authorize to be used on there computers there only guaranteed to work as is out of the box as you bought it ,..


also these boards do not have to meet atx standards and there pci-e slot power may not do the required 75w needed for most higher end cards and can be limited to say 45 or 60w that is all thats needed with the low end factory oem cards that it may of shipped with
[example]
http://en.community.dell.com/cfs-file/__key/communityserver-discussions-components-files/3514/1030.DESKTOP.jpg

in the end any upgrade you do is all your own risk . the prebuilt manufactures only guarantees there computers work as sold to you as is out of the box from there factory with what they put on it , not a drop more

there in business to sell you whole ready to go computers , and dont worry about you upgrading them or giving you support to do so . thats not how they make there money they prefer you run to wal-mart and buy there ''better'' latest models


may check HP forums to see whats said ?

http://h30434.www3.hp.com/t5/Desktop-Hardware-and-Upgrade-Questions/HP-Compaq-Elite-8200-MT-GPU-upgrade/td-p/5506460

https://h30434.www3.hp.com/t5/Desktop-Hardware-and-Upgrade-Questions/Graphics-Card-upgrade-for-8200-Elite-Small-Form-Factor/td-p/5775776

''READ PAGE 2-3, Under SFF models ---
that sets your limitations (Low Profile, Maximum 25 watts in PCIe Graphics x16 slot).''

http://h30434.www3.hp.com/t5/Desktop-Hardware-and-Upgrade-Questions/8200-Elite-SFF-Graphics-upgrade/td-p/4786138

maybe more to look over ?