performance jpeg on phi

Hello.

I am new in Phi world. I tested jpeg encoding performance (tested on image 1680x1050, single thread):

14 ms - xeon E5-2620 - libjpeg-turbo with SIMD
39 ms - xeon E5-2620 - libjpeg-turbo without SIMD
24 ms - xeon E5-2620 - intel ijg80b with IPP
42 ms - xeon E5-2620 - intel ijg80b without IPP (#undef USE_IPP)
386 ms - xeon Phi 31S1P - native intel ijg80b with IPP
557 ms - xeon Phi 31S1P - native intel ijg80b without IPP (#undef USE_IPP)
435 ms - xeon Phi 31S1P - native libjpeg-turbo without SIMD

Is the performance on Phi so bad even with IPP "acceleration" (nearly 28x) ?
Is there any better Phi implementation of jpeg encoding ?

Thanks for answers and happy new year, Martin