Yep, the CPU speed setting is in the recovery menu.
As for converting videos to full-screen AVC, I suggest using 3GP_Converter (the free one). You can use the following settings, or modify them to your preferences. Run the program once and it should make a file called 'Transcoding.ini'; just edit this file in Notepad and add the following:
Code:
[ItemXX]
Title=AVC 480x272 768 kbps 1-pass
TitleE=AVC 480x272 768 kbps 1-pass
Command0=""<%AppPath%>\cores\ffmpeg" -y -i "<%InputFile%>" -title "<%Title%>" -timestamp "<%TimeStamp%>" -bitexact -vcodec h264 -coder 1 -bufsize 128 -g 250 -s 480x272 -r 29.97 -b 768 -acodec aac -ac 2 -ar 48000 -ab 64 -f psp "<%OutputPath%>MAQ<%RandomNumber5%>.MP4""
Command1=""<%AppPath%>\cores\ffmpeg" -y -i "<%InputFile%>" -f image2 -ss 5 -vframes 1 -s 160x120 -an "<%OutputPath%>MAQ<%RandomNumber5%>.THM""
[ItemYY]
Title=AVC 480x272 512 kbps 2-pass
TitleE=AVC 480x272 512 kbps 2-pass
Command0=""<%AppPath%>\cores\ffmpeg" -y -i "<%InputFile%>" -title "<%Title%>" -timestamp "<%TimeStamp%>" -bitexact -vcodec h264 -coder 1 -bufsize 128 -g 250 -s 480x272 -r 29.97 -b 512 -passlogfile "<%OutputFile%>" -pass 1 -acodec aac -ac 2 -ar 48000 -ab 64 -f psp "<%OutputPath%>MAQ<%RandomNumber5%>.MP4""
Command1=""<%AppPath%>\cores\ffmpeg" -y -i "<%InputFile%>" -title "<%Title%>" -timestamp "<%TimeStamp%>" -bitexact -vcodec h264 -coder 1 -bufsize 128 -g 250 -s 480x272 -r 29.97 -b 512 -passlogfile "<%OutputFile%>" -pass 2 -acodec aac -ac 2 -ar 48000 -ab 64 -f psp "<%OutputPath%>MAQ<%RandomNumber5%>.MP4""
Command2="rm "<%OutputFile%>-0.log""
Command3=""<%AppPath%>\cores\ffmpeg" -y -i "<%InputFile%>" -f image2 -ss 5 -vframes 1 -s 160x120 -an "<%OutputPath%>MAQ<%RandomNumber5%>.THM""
Where it says 'ItemXX' and 'ItemYY', just change the numbers to whatever is available next after the previous settings; by default I think it's Item18 and Item19.
Both these settings worked for me; they were suggested over on the Lan.st forums, where the OE devs tend to hang out.