strange behavior of dual GPU clock speed clock speed

This is a newbie’s question.

I have two GeForce 8800 GTX cards on a motherboard.
After booting the system, I get this message from devicequiery;
#############################################
device 0: “GeForce 8800 GTX”
Revision number: 1.0
Total amount of global memory: 804585472 bytes
Total amount of constant memory: 65536 bytes
Total amount of shared memory per block: 16384 bytes
Total number of registers available per block: 8192
Warp size: 32
Maximum number of threads per block: 512
Maximum sizes of each dimension of a block: 512 x 512 x 64
Maximum sizes of each dimension of a grid: 65535 x 65535 x 1
Maximum memory pitch: 262144 bytes
Texture alignment: 256 bytes
Clock rate: 1188000 kilohertz
Time for cudaSetDevice is 0.005 in ms

device 1: “GeForce 8800 GTX”
Revision number: 1.0
Total amount of global memory: 805044224 bytes
Total amount of constant memory: 65536 bytes
Total amount of shared memory per block: 16384 bytes
Total number of registers available per block: 8192
Warp size: 32
Maximum number of threads per block: 512
Maximum sizes of each dimension of a block: 512 x 512 x 64
Maximum sizes of each dimension of a grid: 65535 x 65535 x 1
Maximum memory pitch: 262144 bytes
Texture alignment: 256 bytes
Clock rate: 1350000 kilohertz

##########################################
It says that device 0 has a clock rate 1.18 Ghz while the device 1 has
1.35 Ghz <img src=‘http://hqnveipbwb20/public/style_emoticons/<#EMO_DIR#>/crying.gif’ class=‘bbc_emoticon’ alt=’:’(’ /> . But after startx-ing, I get the clock rate of the device 0 swithed to
1.35 Ghz. I wonder whether this is common or specific to my machine.

The device driver is a version of x86_64 Kernel Module 169.09 and
the os kernel version is 2.6.23.12-52.fc7 #1 SMP.

And there is another question. After booting, the super user has to run any
cuda application in order for other users to see the muti-gpu cards.
Before that the user can see only the first cards.

Many thanks.

Juhan

You do load the nvidia driver module at startup?

Yes, the nvidia module is loaded automatically, and the device files are created with proper permission modes to write and read for users. And I also found that the clock speed switches between those two values at times while the system is on. I am totally confused <img src=‘http://hqnveipbwb20/public/style_emoticons/<#EMO_DIR#>/crying.gif’ class=‘bbc_emoticon’ alt=’:’(’ /> . Possibly it may be the hardware problem in the card?