Motherboard clock speed

Hi I'm trying to purchase a motherboard and I want it to have good specs for games. I am stuck between the Intel 945GTPLKR or the 925x. The only thing thats confusing me about these two mobos is that the 945 says its core speed is 333mhz. http://indigo.intel.com/compare_cpu/showchart.aspx?mmID=8765&familyID=10&culture=en-US The 925x say its clock speed is N/a and I don't know why. http://indigo.intel.com/compare_cpu/showchart.aspx?mmID=103&familyID=10&culture=en-US Is a mobo's core speed important and if it is whats a good core speed or can someone explain core speed for me and It would be greratly appreciated so I can finally get a computer running with games.
Thanks in advance guys

The core speed spec you are asking about is for the on-board graphics (GPU core speed). The other motherboard does not have on-board graphics (you need to add a vid card). You don't want lame on-board graphics if you are a gamer and you don't want an Intel brand motherboard if you want to overclock.

What CPU, RAM, and vid card are you planning on using? That will help us recommend a better motherboard.

I'm using an intel 530J 3.0 processor, geforce 7800 GT, and
2 GB (2x1GB) Geil RAM DDR-2 667. So by having these onboard graphics and shutting them down shouldn't effect gameplay or will it?

Right, if you disable the on-board graphics in the BIOS, then it will work ok with a vid card. Ok, is your vid card a PCI-Express? Is the CPU a socket LGA775? If so, then either of those listed motherboards will work, but you can't overclock an Intel brand motherboard (at least not much). I'd recommend either Abit or Asus. If you want a great board that will support the dual core Pentium D (in case you ever decide to upgrade the processor) then look at the Asus P5WD2 or Abit AW8. If you want a great motherboard for a low price that will work with what you have and you don't care about the dual core CPUs, then check out the Abit AA8XE (I have an overclocking sticky post guide that covers this mobo in the Abit section).