We have a "SQLServer 2005 SP3 32bit Enterprise Edition" running on a 32 bit Windows 2003 32bit Enterprise Edition 12GB RAM with AWE enabled using RAID5(5 pysical disks).

We tuned AWE to enabled and restart sqlserver this afternoon after work, hope the performance will be better than old time.

But there is something that we are very confused.

On working days, SQLServer has a very bad performance. When we are looking for reasons, we check Windows Performance counter.

Avg. Disk Read Queue Lenght > 140
Avg. Disk Write Queue Length < 1
SQL Server Buffer Cache Hit Ratio > 96%
%Processor Time < 30%
SQL Server Total Server Memory < 1.8G

Obviously, without AWE enabled, SQL Server can use only less than 2G memory. My Question is:

1. why "SQL Server Total server Memory" is less than 2G?I think SQL Server will use all 2G process address space. Does this counter count anything out?
2. we known that sql server is sufferring lack of memory, but why "buffer hit ratio“ is as high as 96?

Any advice is welcomed!