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5k or 100k is the right Item Count per Folder in Outlook 2010/Exchange 2010

Hello, I need your help in understanding what the REAL # of items permitted in a given folder within Outlook 2010/Exchange 2010 regarding performance. This article says 5,000 and mentions Exchange 2010 but in the Applies to only includes Exchange 2003 STD & Enterprise. http://support.microsoft.com/Default.aspx?id=905803 
This article seems to say that 100,000 items in core folders is the proper limit where performance is concerned. http://technet.microsoft.com/en-us/library/ee832791%28EXCHG.140%29.aspx 

So which is it 5,000 or 100,000 Item Count per Folder for Outlook 2010/Exchange 2010?

Thanks.
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Aaron TomoskyDirector, SD-WAN Solutions

Commented:
I've had outlook get unhappy with 5k. Doesn't matter if it's exchange, pop, imap, fake exchange (Kerio)...

Commented:
For mailbox on Exchange 2010 it is 1,00,000 item count and for mailbox on E2K3 it is 5000 item count
Blue Street TechLast Knight
Distinguished Expert 2018

Author

Commented:
@aarontomosky: Thanks for your response. Sorry for my delay - today was hectic. Have you had bad experiences with Exch 2k7 and/or 2010?

@pravinkb: This is my point; http://support.microsoft.com/Default.aspx?id=905803 specifically calls out Exch 2010 in the first paragraph. If this is true it contradicts what you are saying and http://technet.microsoft.com/en-us/library/ee832791%28EXCHG.140%29.aspx. Please elaborate.


Blue Street TechLast Knight
Distinguished Expert 2018

Author

Commented:
@ALL: it got me thinking that maybe Exch 2010 has limits on item counts of 100,000 but Outlook has limits on item counts of 5,000? Could this be the case? There is still a contradiction in the tech net vs KB article though. I need some solid facts to back up opinions here or at least to make a point. Thanks!
Aaron TomoskyDirector, SD-WAN Solutions

Commented:
I didn't say outlook has a hard limit of 5000, far from it. It does start doin weird things and significantly slows down though. The worst is in a synched folder like imbox, or trash.  I had a user get up to 8000 in the inbox and new mail took 15 min to arrive. By the time he hit 9000 he didn't get any new mail.
Aaron TomoskyDirector, SD-WAN Solutions

Commented:
Oh and to answer your question, mostly 2010 and 2011 right now. A few 07 still hangin around. 2010 and 2011 seem to get corrupted stores less but still chug on the large folders.
Blue Street TechLast Knight
Distinguished Expert 2018

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Commented:
SO then then the KB article and the tech net article confilict correct? What is the point of allowing 100k items if it boggs down at 5k?
There is no point in nit picking between differing KB articles..... find a number that works for you and create subfolders for anything that exceeds that number.  The real answer is the fewer the better with no hard limits.
Aaron TomoskyDirector, SD-WAN Solutions
Commented:
Agreed. Low hard limits are bad. Remember the 2gb pst size limit and how many problems that caused? Stay under 5k on folders and things run smooth.
Blue Street TechLast Knight
Distinguished Expert 2018

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Commented:
@fl_flyfishing: Thank you for your response! I’m not trying to nitpick but rather understand what the actual limits are because of the incongruences between the two KBs articles. It seems pretty logical to me to understand this.

@aarontomosky: Thank you for the clarity. That is all I was looking for!
Blue Street TechLast Knight
Distinguished Expert 2018

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Commented:

Commented:
Your talking about Critical Item folders here, so Inbox, Sent Items, Deleted Items etc have a limit. for Exchange 2003 this limit was 5000 items, for Exchange 2010 it's 100.000 items and is fact.

Blue Street TechLast Knight
Distinguished Expert 2018

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Commented:
Hi Radweld!

Well the other experts seem to disagree, 5k is the limit no matter what Exchang e2k3 or 2kx. There is a conflict between MSFT KB articles as i pointed out. One article says even in Exchange 2kx there is a 5k limit and another article says what you said.

That is why I created this question…to get to the bottom of it.

Commented:
Exchange 2003 is 5000 items
Exchange 2007 is 20.000 items
Exchange 2010 is 100.000 items

From the horses mouth

http://blogs.technet.com/b/exchange/archive/2009/12/07/3408973.aspx
Blue Street TechLast Knight
Distinguished Expert 2018

Author

Commented:
Yes but what do we say about this: http://support.microsoft.com/Default.aspx?id=905803

Wow! MSFT updated their article after I pointed out this issue to them. Note it was just updated on 12/31/11 and includes all versions of Exchange including 365 plans.
Blue Street TechLast Knight
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Commented:
They did add this clause to the sentence, but still seems to negatate itself as you read past it. "..., depending on the capacity of the Exchange Server environment."
Commented:
your question asked what the real limit is? 5k or 100k? I have pointed out to you that Exchange 2010 has a limit of 100k items. Of course maintaining a lower item count will always improve performance, like only having one mailbox per exchange server will offer great performance. The actual limit for Exchange 2010 is 100k items and not 5k so if you have users with more than 5k items and your not experiencing issues then don't worry too much. Try to keep the item counts down by all means but don't lose sleep over it.
Blue Street TechLast Knight
Distinguished Expert 2018

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Commented:
Thanks for the clarity. I will see if I can split points.
Blue Street TechLast Knight
Distinguished Expert 2018

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Commented:
@ALL: I need to hear from the experts here. I was going to split points between aarontomosky (http:#a37358702) and Radweld (http:#a37368208). Would that be acceptable with everyone? I found greater clarity with Radweld's answer and feel it warrants points. Please advise. If I don't hear from anyone then i will proceed to split the points. Thanks!
Blue Street TechLast Knight
Distinguished Expert 2018

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Commented:
Thanks again for the clarity.

Commented:
Glad to offer my help :-)