I tried this out with my usual cgminer settings that normally net me about 500-600kh/s depending on how my video card is clocked.
setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1
cgminer.exe --scrypt --intensity 13 --gpu-threads 2 --worksize 256 --shaders 1792 --thread-concurrency 12188 --temp-cutoff 90
When I try these settings with VertCoin's modified cgminer, my hash rate is about 15kh/s. I discovered that the reason it is so low is because I am using 2 threads. However, even if I use 1 thread with a higher intensity (I've found I can safely do about 16 on intensity without problems), my hashrate is still only about 280kh/s at most.
Is this normal for this modified scrypt algorithm?
Edit: I'm using a Sapphire HD 7950 3GB with Boost.