Our vendor application database is very TempDB intensive.
The server is virtual (VMWare) with 40 cores and 768GB RAM, running SQL 2012 Enterprise SP3.
All databases including TempDB are on Tier 1 SSD in SAN. We have 10 tempdb data files, each pre-grown to 1GB and they never auto-grow. Same with 70GB log file. Trace Flags 1117 & 1118 are already set.
sys.dm_io_virtual_file_stats shows over 50 Terabytes read/written on tempdb data & log files in past month, with cumulative io_stall of 250 hours or 10 days.
We have already tuned the vendor's code and SPs over past 2 years.
Now, we're thinking of placing tempdb files on RAM Drive since we have a ton of memory. Since tempdb gets destroyed/recreated when server is rebooted, it is an ideal candidate to place on volatile memory which also gets flushed out when server is rebooted.
I've tested this on a lower environment and it has resulted in faster query times but increased CPU usage, because the CPU is doing more work instead of waiting on slow tempdb drive.
Has anyone else put their tempdb on RAM in high oltp production systems? Is there any major disadvantage? Are there any vendors to specifically choose or avoid?