PDI 4.4 is slow on Oracle VM (Windows) when compared to Ubuntu 12.04

Dears,

Thanks in advance for your support

During my project execution, I could notice that PDI 4.4 takes a very long time to complete a job on Oracle VM (Windows 7) when compared to the same execution done on Ubuntu 12.04 linux flavour.

Here is the report,

Ubuntu
Start time: Mon Nov 25 15:26:29 IST 2013
End time: Mon Nov 25 15:30:36 IST 2013
Total elapsed time: 4 minutes, 6 seconds, and 602 milliseconds.

Oracle VM (Windows 7)
Start time: Mon Nov 25 15:07:12 IST 2013
End time: Mon Nov 25 15:16:58 IST 2013
Total elapsed time: 9 minutes, 45 seconds, and 234 milliseconds.

Before the test, I have done the following,

1. Out of 8 GB RAM available on my laptop, I have shared 3.5 GB to Oracle VM which is upper limit. Beyond this, VM will not utilise the exceeded part.
2. I have shutdown all the other applications.
3. Set the heap space to 1024 MB

if "%PENTAHO_DI_JAVA_OPTIONS%"=="" set PENTAHO_DI_JAVA_OPTIONS="-Xmx1024m" "-XX:MaxPermSize=512m"

Please let me know your comments and suggestions.

As far as I know, VM takes shared CPU and memory from host OS (On my laptop, Host=Ubuntu) and this is the main reason, the performance of PDI is slow on VM.