[imp] Memory usage in new IMP

[Ross Becker]

Hiyas folks,
     I've been running IMP 3.2.1 for about a year now, and this week we 
had an issue with users being unable to send attachments.  The 
underlying problem turned out to be related to amavisd/clamav, but in 
the process of tracking this down, we discovered some problems with IMP; 
turns out that if a message had even a 2 megabyte attachment, when it 
was saved in the "sent" folder, the attachment would be silently 
missing.  I tracked this down to be PHP running out of memory when 
copying the message to the sent folder. The configured memory limit of 
PHP on this machine was 16 megabytes.

Can anyone tell me if IMP 4.x has improved memory use in situations like 
this?  It doesnt seem to me that a 2 megabyte attachment ought to run 
PHP out of memory at 16 meg process limit.

Thanks
   Ross