Speed difference between 7.0.5.1-7.0.5.0

[LignGeorge]

I tried to compress to ISO pirates of the carribbean 3 from 37 GB to BD25.I had v7.0.5.1 installed on my pc(windows 7 64bit).The compression with this version war vey slow only 2.5MB/s.I rolled back to 7.0.5.0 and I got 5.5MB/s
What's wrong with v7.0.5.1?(I did't have any programe running oran andivirus scan during both compressions.also the file on HDD was the same).
DVDFab 7.0.5.1 (2010/05/02 12:30:08)

0m 00.84s: option dvd2dvd 1 dvd2mobile 1 bluray2bluray 1 file2mobile 1 filemover 1
0m 09.12s: detected blu-ray
0m 09.12s: iso E:\50GB bluray\PIRATES OF THE CARIBBEAN 3.iso
0m 09.12s: volume label PIRATES OF THE CARIBBEAN 3
0m 10.95s: root 3C9971E7________PIRATES OF THE CARIBBEAN 3:PIRATES OF THE CARIBBEAN 3:PIRATES OF THE CARIBBEAN 3:PIRATES OF THE CARIBBEAN 3
0m 10.96s: aacs 0 bd+ 0
0m 10.96s: got discinfo
0m 10.96s: got bdmv
0m 10.99s: got extended bdinfo
2m 20.29s: groups clips(00001.m2ts,)
2m 20.35s: groups playtime(10110725 ms)
2m 20.41s: Video reencode bitrate (14322 kbps)
2m 20.41s: processing source(00001.m2ts)
2m 20.41s: try to use gpu acceleration(1) for video decoding
2m 20.43s: CUDA GPU acceleration for video decoding enabled
2m 26.50s: filter(1 m:4): not get decoded frame(1-3)
6m 27.97s: group(00001.m2ts ) playtime(10110725 ms) source(0 MB) request(23700 MB) real(485 MB) bitrate(14322 kbps)
6m 27.97s: groups request(23700 MB, 23700 MB) real(485 MB) bitrate(14322 kbps)


DVDFab 7.0.5.0 (2010/05/02 12:37:13)

0m 00.65s: option dvd2dvd 1 dvd2mobile 1 bluray2bluray 1 file2mobile 1 filemover 1
0m 12.52s: detected blu-ray
0m 12.52s: iso E:\50GB bluray\PIRATES OF THE CARIBBEAN 3.iso
0m 12.52s: volume label PIRATES OF THE CARIBBEAN 3
0m 14.36s: root 3C9971E7________PIRATES OF THE CARIBBEAN 3:PIRATES OF THE CARIBBEAN 3:PIRATES OF THE CARIBBEAN 3:PIRATES OF THE CARIBBEAN 3
0m 14.36s: aacs 0 bd+ 0
0m 14.43s: got discinfo
0m 14.43s: got bdmv
0m 14.46s: got extended bdinfo
1m 55.81s: groups clips(00001.m2ts,)
1m 55.83s: groups playtime(10110725 ms)
1m 55.83s: Video reencode bitrate (14347 kbps)
1m 55.84s: processing source(00001.m2ts)
1m 55.84s: try to use gpu acceleration(1) for video decoding
1m 55.97s: CUDA GPU acceleration for video decoding enabled
2m 01.49s: filter(1 m:4): not get decoded frame(1-3)

[LignGeorge]

I solved the mystery ,the high quality encoding(slower)