FFMPEG : With hardware accelerated H264 encode (nvenc_h264 ) Dead slow on Amazon G2 instance

Hello There,

FFMPEG when compiled with “–enable-nonfree --enable-gpl --enable-version3 --enable-shared --enable-pthreads –enable-nvenc --enable-runtime-cpudetect --disable-doc --enable-libmp3lame” options gives abysmal performance when executed on Amazon G2 instance( g2.2xlarge, GRID K520).

E.g. For 5.22 mins BVE_Localize.mp4 file took 66 seconds
time ffmpeg -y -i BVE_Localize.mp4 -strict -2 -vcodec nvenc_h264 -b 5000k -acodec aac -ab 256k -f mpegts BVELocalize.ts

real 1m6.990s, user 2m56.040s , sys 0m1.944s

Above command when executed on Dell-Precision-T1700 (Xeon Dual core, Quadro K620) based workstation takes

real 0m41.572s , user 1m53.621s , sys 0m1.434s

Please help improve performance of ffmpeg on Amazon G2 instance. What do you think I might be missing
I am using G2 (Ubuntu 14.04 64 bit, Cuda 7.0 , 352.55 drivers, MSI disabled)