Is the OldLady a GS3 version? Are your other "gigs" GS3 versions, or are they smaller in size?
I don't know any reason why your Korg Triton would make any impact at all. It simply generates midi note and controller data, identical to any midi controller. I would therefore conclude the problem may be due to the power of your computer. These new large sample libraries demand a lot of system resources, especially GS3.
it's Gs3 and running on a standalone Pc 2,67 and 1 gig ram !...it's only running gs3...its the big old lady .gig that gives the problem...the bosendorfer270 and the steinway le works fine...but i like the old lady the most and will use that the most in my projects