PE 860 en R300 slow Performance same but different speeds XEN Express

[L.P.H. van Belle]

Hi due to performance problems im testing on 2 servers.
Both servers have lates firmwares for bios BMC and SAS controllers.
 
1) this is ok. 
PE 860, Intel(R) Xeon(R) CPU           X3220  @ 2.40GHz, 
SAS1068 PCI-X Fusion-MPT SAS (rev 01)
 
Xen Express 4.0.1 with kernel 2.6.18-8.1.8.el5.xs4.0.1.125.163xen
 
hdparm -tT /dev/sda
/dev/sda:
 Timing cached reads:   12796 MB in  2.00 seconds = 6410.67 MB/sec
 Timing buffered disk reads:  286 MB in  3.01 seconds =  95.15 MB/sec

 
2) this is very slow. 
PE R300, Intel(R) Xeon(R) CPU           X3323  @ 2.50GHz 
Symbios Logic SAS1068E PCI-Express Fusion-MPT SAS (rev 08)
 
Xen Express 4.1.0 with kernel  2.6.18-53.1.13.el5.xs4.1.0.254.273xen
 
hdparm -tT /dev/sda
/dev/sda:
 Timing cached reads:   7232 MB in  2.00 seconds = 3619.74 MB/sec
 Timing buffered disk reads:  102 MB in  3.77 seconds =  27.09 MB/sec


harddisks are the same 140 Gb 10K rpm.
 
only the raid controller changed.
 
whats the problem here and how can give a hint howto fix this.
 
 
Louis
 
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