>Marc,
>
>>As you suggest it, I compare the two Query plans. As I own a backup of the database from today morning, I have the same plan and the same amount of row.
>
>If you are running the exact same database then that would rule out things like index differences etc.
>
>>When I execute another stored procedure here, the first time, it take about 4 sec. and 5 sec. at my customer. The second time, it take 1 sec. here and still 5 seconds at my customer Do you think that this can be due to the cache?
>>
>>I nnotice another difference, My SQL Server is version 8.00.760 SP3 Developer Edition, My customer is 8.00.760 SP3 Enterprise Edition
>
>It sounds like load/resource issues to me then (but I am not a SQL Server configuration expert by any stretch of the imagination *s*). Do they have more concurrent load on the box than you? Is the server machine dedicated? Does it have enough CPU(s) and memory? They should be able to go into the performance monitoring tools and see what the processor load is running at while the SP is being called.

Yes, the server is dedicated to SQL only... I think it's enought powerfull. Specs are an IBM X-Series 445, with Quad proc XEON 3 Ghz 4Mo Cache, 8Go RAM, 6HD 15000rpm Raid-5. I was alone connected on the DB with the Query Analyser, directly on the server to make tests.

but I don't understand why many SP are faster than here, and other are slower (it's not logical)