I agree with the above recommendations to use Vienna Ensemble Pro (VEP). I’ve never used it myself, but it’s popular and by my researching alone, I think it would be a very good solution to a problem such as yours. You’ve got a powerful DAW, just sounds like you may be throwing too much at it. Still, check your resource usage as recommended above, if you haven’t already.
However great VEP user’s claim it is, it isn’t the only solution…and that’s just for LAN solutions. VEP does have their followers that swear by it. By stating “LIVE”, do you mean for ‘performing for an audience’, or do you mean in ‘real-time in your studio?’ I didn’t know about VEP being more efficient even on the same computer as stated above, but I’m a believer of using a dedicated 2nd computer to off-load & run all VSTi’s from, letting my audio machine to handle it’s functions without VSTi’s bringing it to a halt.
I almost bought VEP myself, after trying a few other solutions, some worked well, some not so much for me. But then I discovered SYNC, with 2 machines together and the transport functions linked, now I don’t need VEP. With sync capability, I realized I can record my midi directly into my dedicated VSTi machine, and didn’t need to send midi between machines at all, as I did with other solutions. The VSTi machine can send back either 8 channels of digital audio via adat, or a stereo sub-mix via s/pdif…I find a stereo sub-mix to be all I need, as I can do whatever is needed locally in that machine before sending it into my audio machine, where I monitor & record the sub-mix.
There are various ways to sync machines as well… MMC, VST System Link, a separate hardware syncing device etc. I’ve read of several others syncing 3 to 5 machines together. What method of sync can depend on what computers you’re using…eg; System Link is proprietary & requires some version of Cubase or Nuendo on each machine, which is fine for a Cubase user with more than one version. Other solutions are more universal for running cross platforms…different OS & DAW softwares.
Whatever solution is chosen, the idea remains the same…to take the load off of your main DAW computer. Different people have had great success with the option of their own choosing. It seems that many choose VEP like they did years ago with the Shure SM-57 mic…as being almost a ‘standard’ & ‘sure thing’ to Get R’ Done. But I know of many who very happily do not use VEP…including myself.