No, not at all. Both are DX10 class hardware and the 4850 is vastly superior. If you're not going to game or won't use madVR, the 2500k's iGPU would be the better choice for an HTPC, the 4850 is going to produce a noticeable amount of heat/increased fan speeds overall.
The 4850 is legacy hardware, AMD isn't updating its drivers anymore (someone got its old drivers to install on W10 on another thread). I don't know about Intel's stance on the HD3000.