I've recently installed fedora 16 x86_64 with KDE and I find that my machine seems to go into high cpu usage for about one minute out of every few minutes.
This turns out to be due to the following (output from ps faxww)
29098 ?        Sl     1:38 /usr/libexec/packagekitd
 9528 ?        R      1:12  \_ /usr/bin/python /usr/share/PackageKit/helpers/yum/yumBackend.py get-packages unknown

I'm trying to figure out why it does this so often and how I can control it. 
Software management - system settings indicates check for updates = daily.

Running pkmon shows
$ pkmon
Transactions:
 [none]
network status=wifi
Transactions:
 1	/484_adceaebc_data
/484_adceaebc_data	status       setup
/484_adceaebc_data	percentage   -1
/484_adceaebc_data	role         refresh-cache
Transactions:
 1	/484_adceaebc_data
 2	/486_cbdbaabb_data
/486_cbdbaabb_data	status       wait
/486_cbdbaabb_data	allow_cancel 1
/486_cbdbaabb_data	percentage   -1
/486_cbdbaabb_data	role         get-updates
/484_adceaebc_data	status       refresh-cache
/484_adceaebc_data	allow_cancel 1
/484_adceaebc_data	percentage   0
/484_adceaebc_data	percentage   95
/484_adceaebc_data	percentage   100
daemon locked=1
/484_adceaebc_data	status       finished
/484_adceaebc_data	allow_cancel 0
/484_adceaebc_data	status       generate-package-list
/484_adceaebc_data	percentage   -1
/484_adceaebc_data	status       finished
/484_adceaebc_data	exit code: success
Transactions:
 1	/486_cbdbaabb_data
updates-changed
daemon locked=0
/486_cbdbaabb_data	status       setup
/486_cbdbaabb_data	allow_cancel 0
/486_cbdbaabb_data	status       info
/486_cbdbaabb_data	allow_cancel 1
daemon locked=1
/486_cbdbaabb_data	status       finished
/486_cbdbaabb_data	allow_cancel 0
/486_cbdbaabb_data	exit code: success
Transactions:
 [none]
daemon locked=0
 ...

/usr/libexec/packagekitd --verbose 
08:18:51	PackageKit	Verbose debugging enabled (on console 0)
08:18:51	PackageKit	keep_environment: 0

08:18:51	PackageKit	using config file '/etc/PackageKit/PackageKit.conf'
08:18:51	PackageKit	syslog fucntionality disabled
08:18:51	PackageKit	Log all transactions: 1
08:18:51	PackageKit	daemon shutdown set to 300 seconds
08:18:51	PackageKit	using default backend yum,zif
08:18:51	PackageKit	watching for changes: /proc/net/route
08:18:51	PackageKit	Trying to load : yum
08:18:51	PackageKit	dlopening '/usr/lib64/packagekit-backend/libpk_backend_yum.so'
08:18:51	PackageKit	clearing download cache at /var/cache/PackageKit/downloads
08:18:51	PackageKit-Yum	backend: initialize
08:18:51	PackageKit-Yum	loading configuration from /etc/PackageKit/Yum.conf
08:18:51	PackageKit	active connections: 1
08:18:51	PackageKit	is_default: 1
08:18:51	PackageKit	number of devices: 1
08:18:51	PackageKit	type: 2
08:18:51	PackageKit	network state is wifi
--More-- 

08:18:51	PackageKit	watching for changes: /etc/PackageKit/PackageKit.conf
08:18:51	PackageKit	watching for changes: /usr/sbin/packagekitd
08:18:51	PackageKit	ProxyHTTP read error: Key file does not have key 'ProxyHTTP'
08:18:51	PackageKit	ProxyHTTPS read error: Key file does not have key 'ProxyHTTPS'
08:18:51	PackageKit	ProxyFTP read error: Key file does not have key 'ProxyFTP'
08:18:51	PackageKit	ProxySOCKS read error: Key file does not have key 'ProxySOCKS'
08:18:51	PackageKit	NoProxy read error: Key file does not have key 'NoProxy'
08:18:51	PackageKit	PAC read error: Key file does not have key 'PAC'08:18:51	PackageKit	install root now /
08:18:51	PackageKit	Cannot connect to HAL: Could not get owner of name 'org.freedesktop.Hal': no such name
08:18:51	PackageKit	trying to open database '/var/lib/PackageKit/transactions.db'
08:18:51	PackageKit	job count is now at 498
08:18:51	PackageKit	notify::connected
08:18:56	PackageKit	idle is 5
08:19:01	PackageKit	idle is 10
--More--
08:19:06	PackageKit	idle is 15
--More-- 

08:19:11	PackageKit	idle is 20
08:19:16	PackageKit	idle is 25
08:19:21	PackageKit	idle is 30