Thanks for everyones help. Finally got to the bottom of this. It appears to be a clash between SQL2000 and 2008

SQL 2008

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update MSreplication_subscriptions set transaction_timestamp = cast(@P1 as binary(15)) +...

I think the async network io is a red herring. Network cards are full duplex and data transfer rates comparable.

Over the weekend we set up a second subscription to...

Update stats did not resolve the issue unfortunately.

We have also just expanded the TempDB from 6GB to 80GB based on a recommendation from Microsoft.

8hrs and the update stats is still going! It isn't perfect but performance does seem to be better. Should have a good idea tomorrow morning.

We had updated the stats on specific tables, but have now scheduled in an update with full scan for tomorrow morning

Network hasn't changed so that was ruled out.

Stats were updated for the MSreplication_subscriptions table.

We will do some comparing of the repl procs today to see if that shows anything.

We...

We have also just expanded tempDB on the subscriber server to have 8 data files to match the number of processors.

Tracer Token show Publisher to Distributor (same box) as a couple of secs and all the latency is Distributor to Subscriber - 12 minutes in the one I just did....

Only differences are BCPBatchSize and QueryTimeout which we haven't changed and PollingInterval which changed to 5 by default and we have changed back to 10

Distribution Agent Log

************************ STATISTICS SINCE AGENT STARTED ***********************

11-14-2013 13:20:45

Total Run Time (ms) : 394605 Total Work Time : 389457

Total Num Trans : 5194 Num Trans/Sec...

Disk is now significantly better

Was previously 2 Utlra SCSI 420 72GB drives RAID1-0 and is now 4 SAS 300GB drives 2 RAID1-0 pairs.

Yes all going to the same database/objects. The split is 80 on 2000 and 60 on 2008

Cheers

Some are worse than others, but there is latency across all the new servers. There was a correlation to the number of records in msrepl_commans and performance. But even when...

Cheers for the response. The publisher is its own distributor, there isn't a separate server for this. I will post some outputs from the Distribution and Log Reader agents shortly

For reference all changes except the @status and PollingInterval have been made at 2 or 3 of the 60 new servers to test, not at all 60.