so I am still looking in PCI-E though right? ....
You know IT REALLY IRRITATES ME when I take my time an look up and provide a link and some OP is too lazy to figure it out! But yes, if you must be spoon fed it is a PCIe x16 video slot.
But the system reqs say that I needs 400w PSU. .... Can I get away with the 250 watt?
As to whether the 250W PSU will work that is a lot of hypothesis to go along with facts.
The maker, Bestec does not do a bad job constructing their PSUs BUT all PC makers use the PSU to cut pricing corners so it is definitely not the best either.
Secondly, as you have found out 250W is a pretty poor amount of power on any modern PC and also where they cut a pricing corner.
Lastly, a PSU loses the ability to actually put out the max. power it was rated for as it ages so it is unlikely to be capable of putting put 250W now, if it ever was.
But most people rarely use a GPU at anywhere near the max. power levels.
And it is only the +12V power that matters for the GPU. The GPU chip maker provides a recommendation for a power capacity that is overall (and covers 3.3V and 5V as well) to cover the system. To cover their butts this is usually grossly over estimated which is not bad engineering practice and makes the lawyers/liability Ins. Cos. happy.
If the TDP of the particular GPU is calculated
the max. number of watts the GPU can use on the 12V rail can be determined. My rule of thumb is to not exceed 25% of the 12V rail on a cheat. That leaves 75% for the rest of the system which should be more than enough.
You GF's PSU has 14A output on the 12V rail which is not very good...more amps on the 3.3 and 5V rails (18 and 25A respectively). An old ATX pre-1.3 rev. That leaves you with about 46W for the GPU card...when the PSU was new assuming it ever actually supplied that much claimed power.
That means the nVidia 8400 or even the 8500 will work despite what the card maker recommends. But why would you want that old junk?The HD6450
runs rings around the 8400 for the same price (but neither are very good gaming cards), while the HD6570 (with DDR3) actually meets GuildWar2's min reqs
. and scrapes by with a 44W TDP.
edit: Ran across this