4096 texture question

What kind of performance hit would 4096 textures make on a PC? My mod will have 2 textures that are 4096x4096 (6 in total since both textures will also have a specular and a normal map layer) all other textures will be 512x512 and 1024x1024 max about 10 in total (actually 20 accounting for layers)

Would the performance hit be drastic or relatively small?

 

Ok Ill have to check the way the textures look, 2048 may be good enough. the UV Islands im using are kinda small because theres so much on one, I dont want the textures to look low quality