Your performance should be great! vfp7t.dll (and vfp6t.dll SP5) takes care of any multithreading issues in the past. This combination is extremely fast and scalable and you should be pleased with the results. Performance should be as good or better than Foxisapi or wwc and it's easier to install and more stable than Foxisapi.
If you want to check out some example apps written this way, go to:
http://www.activevfp.com/AVFPdemo15/AVFPdemo15.asp
We've added some utilities to make some things easier like HTTP upload, using HTML tables and templates,charts, e-mail, etc. Our next version will have a debugging tool so that you can step through the .dll code.
Check out the VFP ASP/ASP.NET resource page for more info:
http://www.activevfp.com/dev
specifically:
http://www.activevfp.com/dev/dna08.htm
Also, always remember to use COMRETURNERROR in your error handler ...

>I plan to develop a web site using ASP as front-end and COM objects(DLL) created with VFP7 as back-end.
>
>How is this combination going to work in terms of performance?
>I am afraid that sending simultaneous request will slow down the response time.
>
>Any thoughts?
>
>Thanks