If you are backtesting a strategy that allows intrabar order generation, then it seems to me that Look Inside Bar Backtesting is essential — am I right?

And if you are doing that, which seems to me to be the only way that you can simulate what will happen in a live market with stop orders and limits being triggered, then it seems to me to be also essential that you go right down to tick data.

Obviously this is incredibly slow, and for me results in lots of crashes, despite running on a very fast VPS.

Am I right in thinking there's no other way to do it - what is everybody else doing?

It is useful if you are using stop or limit orders but obviously still uses past data, so it does not say your real-time performance will be the same.

But it is not necessary if using "today at close" or "next day at open" orders.

Bob