Qemu slow disk throughput

I am doing some development for a UN community site, using Zope/Plone. I uses Qemu for hosting the guest OS for my development environment.

For 2 days, I keep wondering why Zope/Plone loads damn slow on the qemu machine eventhough I have allocated both cores of the processor, and 512RAM for it. 15 minutes simply to start up is really not desirable. I kept on investigating and guess what:

[root@unapcict ~]# /sbin/hdparm -t /dev/hda

/dev/hda:
Timing buffered disk reads: 18 MB in 3.03 seconds = 5.95 MB/sec

Just for a comparison, the host hdd's speed:

[root@Nobuyuki ~]# /sbin/hdparm -t /dev/sdc

/dev/sdc:
Timing buffered disk reads: 174 MB in 3.01 seconds = 57.71 MB/sec

Darn.. So, thats what the reason. Dear lazywebs, anybody know how to improve the speed??.