sql server - SQL Performance Problem IA64

We’ve got a performance problem in production.

QA and DEV environments are 2 instances on the same physical server:

Windows 2003 Enterprise SP2, 32 GB RAM, 1 Quad 3.5 GHz Intel Xeon X5270 (4 cores x64), SQL 2005 SP3 (9.0.4262), SAN Drives

Prod:
Windows 2003 Datacenter SP2, 64 GB RAM, 4 Dual Core 1.6 GHz Intel Family 80000002, Model 6 Itanium (8 cores IA64), SQL 2005 SP3 (9.0.4262), SAN Drives, Veritas Cluster

I am seeing excessive Signal Wait Percentages (> 250%) and Page Reads /s (>50) and Page Writes /s (>25) are both high occasionally.

I did test this query on both QA and PROD and it has the same execution plan and even the same stats:

SELECT 

                top 40000000 * 
INTO 
                dbo.tmp_tbl
FROM
                dbo.tbl
GO

Scan count 1, logical reads 429564, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

As you can see it’s just logical reads, however:
QA: 0:48
Prod: 2:18

So It seems like a processor related issue, however I’m not sure where to go next, any ideas?

Thanks,

Aaron