Which board would be better

right now i have a q6600 g0 steping, runing at 3.6ghz in an asus p5ql-e which is a p43 chpset

but the ram i have which is ocz800 2x2 kit won't allow more then two sticks in that board, and i another 2x2 mushkin kit i want to add so i am limited on the board ram wise

i also have a gigabyte p35 ds3l rev2 board, and want to check performance wise is there a large diffrance with this board compare to the asus board, specificly towards overclocking? and performance? and heat? have a big cooler for cpu

i know it has less connectors like no esata and only 4 sata conectors inside, but thats ok for me, would i still be able to reach the same or close to the same clock speed? right now its 9x400=3600mhz

forgot to mention the asus board has a pcie 2.0 slot works great with my ati 4870, will going down to a 1.1 pcie slot make a huge diffrance for that card?