Is it better to stay with vardiff or is there a particular difficulty with low reject rate?
I am currently using d=8192 and today i can see some pick of 80% or reject
I have been using 8192 on my titan for a week, the highest reject has been 35%, typical is 15-20%.
on my titan it says i am mining at 310 but i typically register about 275 on the pool.
I am thinking about experimenting and seeing if I can find a better difficulty setting.
Titan has some issues with non-LTC mining due to details of how its firmware is designed. I've been working with KnC recently and helped them to improve things. Please make sure you are using the latest firmware which they released recently as it improves Titan performance on coin-switching pools.
Also, I am working on some workarounds on the pool end to optimise them for Titans and its shortcomings. Titan performance on CleverMining should improve any day now, assuming you have the latest firmware installed. There will be an announcement when it's running.