the actual gw version is 24.1 Build 144763!
but on wich server runs groupwise? virtual or on own hardware? How many processors, how many ram!
how many users are on the gw-system!
It is not possible to answer on you task without more details and informations

In this case your questions aren't relevant, because HW is very very powerful. We tried 16 vCPU, 32 GB RAM, SAN is 32 Gbps FC. Split system to two post offices on separate server. Currently there is 100 users on one server. 

As I said, between GroupWise 18 and 23.4 was major slow down. Even the HW was upgraded to HP DL360 Gen10 servers. 

David, I assume you have seen recent threads where we discussed slowness. Especially search activities made GroupWise slow. This was because of outdated libraries (Thomas Stimper was a key contributor for this issue). Therefore a lot of FTFs have been published to wipe out this bug.

So maybe open a case to get a better version. It is not only the client you have to update.

Nevertheless I agree that Groupwise became slower over the years (compared to GW8 i.e.). Maybe it is tribute to new functionality and cooperation with other products.

Diethmar, comparison is done to GW 18, I'm aware of the problems with searching, but this problem is especially only opening an email. Customer has GroupWise on NCS / NSS , can be this cause of the horrible slowness ? 

I assume that you have not change operating system between 18.5 and 23.4 ...

Did you try to access with older clients to gw23.4? Maybe we can find out if the server or the client causes these issues.

What about the good old "deactivate NetBIOS"-Trick?

We are running gw on pretty "old" hardware on HDDs with 500+ users. Everything on one server. Also on nss... The first mails takes 1 or 2 seconds. After that it's fine...

DVA is running fine?

Firewall on gw server on?

Did you see any package drops or errors?

10 to 15 seconds for opening a mail, which you see in your mailbox actually, is definitely too long. But I do not think, that this is related to Groupwise directly but maybe to a network problem. Of course Grouwise got slower over the time. I think somewhere in the transition from 18.0 to 18.5 there was a noticeable slowdown. The longest times I observe, is, if I change folders in the client pane. If the folder contains more than 30.000 mails it needs around 7 to 8 seconds till the folder is displayed - and that on a 10GBit connection to the mail server. In previous versions the time to switch folders was almost unnoticeable.

Quite a time before we had problems with Groupwise and a Cisco switch, that sat between two MTAs. We wondered, why it took so long time to send small emails to mail recipients over the internet. After checking everything, we discovered, that for a still unknown reason the bottleneck was the connection beween the MTAs over this switch. All other traffic - internet surfing, file transfers via ncp or smb/cifs or ftp, ssh etc. - had no perormance issues over this switch, but Groupwise message transfers were incredible slow with a multitude of unnecessary fragmentations. We exchanged the switch and all problems were gone. We did not dig further into the issue as the switch was already out of warranty, but the real strange thing was, that only Groupwise traffic was affected and there was for sure no traffic-prioritization configured.

we have this TID with the 2 options outside of GW that impact performance of GW in a big way

Hi David, been in same spot with one customer already. Happened after upgrade GW 18.4.2 to 23.4. Every other client newer than 18.3 showed same issue, slow opening of some emails, slow opening of contacts, etc. Interesting enough, 18.3 client worked without any issues. Only thing what helped in the end (was told to migrate from nss to xfs, tried all the rebuilds etc) was to create new PO and migrated some users into new PO - helped a ton. I am at start of migrating all users to new PO, so not really sure what will happen after all of them will be on new PO, but maybe would worth a try for you as well.

Thanks for hints, I will try them all.