Spatial reference impact on performance

[ShaningYu]

Scenario Description:
1) Source feature layers' S.R. = 4326
2) In the mxd, set the frame's S.R. as 102100.
3) Load the source feature layers.
4) Publish the mxd as a map service.
5) Add the layers in the published map service as dynamic layers, which overlay on ESRI's basemaps.
Qestion:  Will this impact the performance?

[TanuHoque]

Yes.
Depending on number of features and the complexity of features, you may see noticeable difference in the performance.
In your case, every export request will project features on-the-fly which is expensive operation.

If you can, we recommend to project your FeatureClass to the destination SRS (i.e. 100210) and publish that as a mapservice.

[TanuHoque · Accepted solution]

another factor that I forgot to mention is the number of simultaneous users using your service.