Midrange graphics card for HP Pavilion m7181 mother board ASUS PTGD-LA

I need to upgrade the graphics card in my HP Pavilion m1718 machine from the factory fitted RV370XT

The problem is knowing what graphics cards will physically fit as the Micro ATX motherboard Motherboard manufacturer's name: ASUS PTGD-LA has an ATX Power Connector directly in line with the PCIEX-16 slot which 'looks' as if it will interfere with any cards longer than rougly 21.5cm





I don't need the latest card and would prefer to keep the noise and power requirements down to about 300W as my powersuply is a Bestec 300W power supply with the following voltages.

+12V 19A
+5V 30A
+3.3V 28A

-12V 0.8A
+5VSB 2A

Does anyone have experience with this motherboard and if so can they confirm whether any of the following will fit and also if the power supply will cope

Nvidia 8800GT / GTS
Nvidia 8600GT / GTS
ATI 3870 / 3850
any other suggestions

I've found it quite difficult to get details on length and power consumption for graphics cards so if anyone who know where this is easily obtained I'd also love to know.

Thanks in advance.

Great answer. Many thanks