I'm planning to build a new PC and I was wondering what the difference
was between the x38 and p35 motherboards.

I was thinking on buying either the
ASUS P5E
or
GIGABYTE GA-P35-DS3R

CPU: e8400
GPU: 8800GT OC (or 9600GT)
RAM: DDR2 800 or 1066

Should I go with the more expensive x38? Or just go for the p35?
I'm planning to overclock the CPU to atleast 3.6 (4, if I can manage it).
Will the mobo matter on that?
Thanks!

X38 has 2 full x16 PCI-E lanes availablle for gfx & they are both PCI-E 2.0 spec.
P35 has 1@x16 + 1@x4 & they are the older PCI-E spec.

Basically it comes down to whether you think that you will ever run Crossfire as there is nothing that needs PCI-E 2.0 yet as we haven't saturated PCI.E 1 yet.

^^^ nailed.

X38 overclocks a bit better than P35, but word is that the P965 beats out X38 & P35 in terms of overclocking 45-nm cpus like the e8400.

X38 & P35 up to around 600fsb
P965 beyond 600fsb (to be exact, P5B DELUXE)

Then again, you'd need extreme cooling for those fsb. Air cooling doesn't cut it.

I'm at 4ghz on P35. 3.6ghz is a given. 4 will require better cooling.

Actually, I'm seeing better results overclocking the P35, at least so far as consistency goes. Using just the available motherboard settings (stock cooling, no voltage mods) most P35 boards can hit 540MHz FSB while only a few X38's can.

I see. I think I'll just go with the p35 since I don't think I'll be using multiple GPUs just yet
and it overclocks fine anyway.

Thanks guys!

then why dont you use asrock newer mob.? they got good spec. & superb low price.