Assassin's Creed uses excessive GPU

99%. if there is no bug what so ever that it shows that the game able to utilize the gpu perfectly. it an old game but it doesn't mean any new gpu will be able to run it easily. 5450 considered as a weak card even at very low resolution. when everything max out even my GTS250 (which is a few times faster than 5450) can't get 60fps for that game with 1600x900 res.

for 1080p try to get at least 6850 or 7770 if you want to play with smooth frame rates (60fps and above) with medium setting in most games.

Would dual HD 5450s be enough to run it at 60fps on medium settings and say 1600x900?

Also does the 0C2KJT motherboard support dual cards?

is it dell motherboard? if it is OEM mobo rarely have extra x16 pci-e mobo. also instead going for dual 5450 it is better to get single more powerful card not to mention crossfire also have it's own problem as well. what is your preferred gaming resolution? if you want to upgrade your gpu you need to double check your psu as well

Assasins creed uses ATI Gpus at full due to the Havok system if i remmer correctly.
I know i had the same situation with my 4850 in crossfire, yet on nvidias 560 Ti, it bearly sweats.

Right now I get 10-15 fps with 1600x900 and low settings.

I don't easily notice low fps, so 15-20 is enough for me, and medium settings. Preferable 1920x1080, but 1600x900 is acceptable.

I don't really have a lot of money right now

I think this motherboard has multiple PCI-E slots,

for 25-30 fps is still fine but any lower than that game will be very sluggish to me. btw for graphic card you will need PCI-E x16 slot. normally you can find two types of PCI-E slot on motherboard x1 and x16. for modern motherboard it is not rare to see boards with single x16 pci-e slot and several x1 slots so you have to be sure that your mobo have at least 2 x16 pcie slot if you want multi gpu setup.

if you really have tight budget at least try looking at 6670 or 7750. at the very least you can have much smoother gaming experience with those card

I'll look into it, thanks for your help