Big latency problem on Cubase Pro8 with iMac

Hi dear all,
I need your help asap !
I’m using an iMac 3To Fusion Drive with the maximum of RAM (supposed to be a beast!), going to a UAD 2 Firewire plugged to my audio card RME Fireface 800 (as asked by Universal Audio to plug … My midi keyboard is the Novation SL61 MK2 and it’s plugged with USB… I’m using many DAW’s as Logic 9 and X, Studio One 2, Ableton Live 9 and Cubase 6, 7, 7.5 & Pro 8.
I’ve added the Automap to all my DAW’s.
There is only one DAW which one I have a seriously BIG problem of latency when I open a new project !!!
My RME buffer is parametered at 512, or 256, or more… whathever… on my Cubase but if I plug only 1 small vst synth as SYLENTH1 or any other synth (they are all officials), I listen the sound nearly 1 second after having pushed the note of my keyboard.
It’s a pitty because I don’t find any solution to my problem…
And more… Since I’ve upgraded from 7.5 to Pro8, I can’t open my old projects with my old versions :frowning:(((

Pleaaaaase help !!!


Try turning off ASIO Guard and see if that remedies the problem.