Oracle on SPARC/SOLARIS is very competetive
From customers I've heard that Oracle is pushing SPARCS to run their Enterprise Database.
Although it cant match Power6+ or latest X86_64 on single thread speed, the Sparc architecture still offers great benefits when it comes to hardware redundancy, storage management and a rock solid OS in the bottom with some nice features you will never see on RHEL (DTrace, ZFS, Fault manager, Service Manager to name a few).
They discount the oracle core licenses so they become competetively regarding price/performance.
The hardware price is nothing compared to the $47.500 per processor list price, and AFAIK no other processor beats the 64threads on T4 or 128threads on T3.
Add up the discounts and the most attactive system to run a large oracle database is on Sparc/Solaris.
The next SPARC T5 will have 128cores and 16K threads and IO backbone to sustain it.
Singlethread will be mediocre but no one else
I work with databases that grows with >10mill rows each day, and I've never seen any need for faster cpus, it is mostly IO and memory. If a single thread is slow, just run them in parallel and you get linear speedup.
When you run queries you need lots of indexes to back you up which makes you IO bound.