Here is the GPU-Z output for an HD5450. It's definitely not a high-performance card intended for gaming. Slower memory, slower RAMDAC, much lower bandwidth, than your GTS card.
But it is a perfectly adequate and acceptable "ordinary" video card for "ordinary" users. Plus, it only costs about $40. It's a reasonable upgrade for low-end machines that only have basic low-end onboard graphics chip with little or no hardware memory, and for that it does its job.
In particular, it's a 1/2-size card, which allows it to be installed in cases that are small form factor or ultra-small form factor. That can be very important.
I've installed three of them in three machines for friends/family. But I've gone with the ASUS Silent (fanless) EAH5450 1GB version
, because I want ZERO NOISE.