Throughput Difference in Form File Upload vs. cURL Upload

curl_upload.sh

# 1.75 MB/s 
curl 'https://mysite.com/test/testUpload.cfm?which=fileUploadAll' -F 'filedata=@/cygdrive/e/garbage/GIS Toolkit 2014/GIS Toolkit 2014/CoC_GIS_State_Tool_IN_2014.zip' --compressed --insecure --limit-rate 1000M

form_upload.cfm

<!--- 0.71 MB/s --->
<cfif isdefined("form.fileData")>
	<cfscript>
	param name="url.which" default="fileUpload";
	destination = expandPath("/mysite_deployment_root/protected/reportmanagement/inbound");
	nameConflict = "overwrite";
	if ( which == "fileUpload" ) {
		result = fileUpload(
			destination=destination,
			nameConflict=nameConflict
		);
	} else {
		result = fileUploadAll(
			destination=destination,
			nameConflict=nameConflict
		);
	}
	</cfscript>
	<cfoutput>#serializeJSON(result)#</cfoutput>
<cfelse>
	<form name="myUpload" enctype="multipart/form-data">
		<cfinput type="file" name="fileData"><br>
		<cfinput type="submit" name="submit">
	</form>
</cfif>

Why is the transfer rate so different? https://groups.google.com/d/msg/lucee/doo5yazongg/kWXzUK-GDQAJ