Here is an email PESfan have received from Konami on the subject of slowdown.
Konami Digital Entertainment is aware that some players of PES2008 are experiencing “stuttering” by their machine when playing on PS3. (This does not occur on other formats). After checking the matter we have found that the problem is primarily taking place where the user is not playing the game in high definition.
The solution to this problem is to play the game on an HD TV (high definition screen) with an HDMI or component cable and the PS3 set to output in 720p resolution or above. This should prevent the problem and allow the player to enjoy the full HD experience provided by their PlayStation 3.
Please note: to achieve high definition it is necessary to use HDMI or component cables instead of the AV (composite) cable supplied with the PS3.
We are continuing to work on finding a solution for those people who do not have access to an HD TV.
In the meantime Konami would like to apologise for any inconvenience caused
This is very dissapointing, considering quite a few people on various websites, including me, have the resolution and cables required, yet the slowdown is still evident. Hopefully they’re not trying to weasel out of a patch and one will be released in the coming weeks.