ok so i know they are both not good at all for gaming but which is better and would the 9400gt run on a 240w power supply (+12=7.5a, +12vcpu=11.5A, +12v=0.15A) all i want to play games like dawn of war 2 would either of these cards be suitable
Hd 5450 is better than gt 9400 in all aspects.hd 5450 just consumes 19w tdp whereas gt consumes 50w.hd 5450 supports dx 11.it will work with your psu.simply hd 5450 wins.
thanks ill look into the 5450, i bought a 5570 but it didnt work with my power supply
It probably didn't work because it's a PCI-Express 2.1 card and you tried installing it into a system that has a PCI-Express 1.x slot. Power requirements had nothing to do with why it didn't work.
The DC7700 is an old system, built in 2006, and has a PCI-Express 1.x slot. Because it's a pre-built, it likely never received the required BIOS support update to allow the PCI-Express 1.x slot-equipped system to recognize and initialize PCI-Express 2.1 cards. (Manufacturers only issued such updates for certain supported systems in 2009, which is when AMD adopted the 2.1 standard and released its HD5000-series cards.) Unfortunately, all AMD HD5000-series cards (including the HD5450 you're considering) are built using the PCI-Express 2.1 standard, meaning none of them will work in a PCI-Express 1.x slot-based system that didn't receive such an update.
As for upgrades that may actually function in that system, you'll have to look for something from the previous generation - the HD4000-series. I've seen several people successfully install low-profile HD4650's in such systems, and even a few install low-profile 9600GT's in them. However, those cards are extremely hard to find (read as: pretty much non-existent) presently.