The issue you have has nothing to do with passing video through your receiver. The issue is due to the video processing carried out by your TV!Hi, thanks for reading. I had an input lag issue with my new TV (audio out of sync with video) which meant that I have to output an HDMI cable from my sky box directly to the TV as well as an optical from the sky box to my 608 amp. I have the same problem with my PS3, however I'm unable to receive sound at the 608 although there is light leaving the optical cable and I'm sure that it is inserted correctly, secondly, even if I got this to work would I have been better off sound wise with HDMI? would some sort of HDMI cable splitter be a better option?
If using optical rather than HDMI in order to convey audio then you are restricted to SD quality audio formats. Only HDMI can convey HD audio formats from your PS3 to a suitably equipped AV receiver. HD formats are used on Blu-ray movie titles.
THere's no benefit gained by outputting video directly to your TV via HDMI while outputting audio via optical to your receiver. The TV is causing the delay, not your receiver and you are limiting your audio to SD quality formats by doing so. Connect your PS3 directly to your receiver via HDMI and look at your TV's video processing settings to see what can be done to reduce the use of video processing. Some TV's have a games mode specifically put in place to reduce the amount of video processing.