disk cache batteries

We finally got thru our fix of disk cache batteries (iSeries 810 only perhaps 4 
years old).
The only clue we had was that the system became extremely slow during a 
conversion test, running about 3 times slower. The CE claimed it shouldn't have 
hit us that hard. I think otherwise - we were running large cpylib, many 
chgpf's of big files, and adding 7 gig of files w/RPG to existing 10 gig.
Manager asking if I can prove it was the batteries (this was our final test 
before go-live). 
Can anyone else confirm losing cache batteries could cause such an effect?

btw- our only clue of hardware problem was wrkdsksts & F11 screen showed disks 
in "degraded" status. After an ipl, we did get following 2 msgs in qsysopr 
queue:
* *Attention*  Contact your hardware service provider now.
Message ID . . . . . . :   CPPEA12       Severity . . . . . . . :   99
A critical system hardware problem has occurred. Critical Message Handler
    has been run.
Message ID . . . . . . :   CPP8988       Severity . . . . . . . :   90

jim franz