I have a 768 MB 460 GTX (mildly OCed) with an e8200 (dual core 2.7 GHz with 8x FSB multiplier), 2 GB DDR2 and a cheap G41 board (whose FSB wall combined with the low CPU multiplier prevents me from OCing the CPU more than about 100 MHz). I am running at 1440x900 (the native resolution of my monitor). I am running Windows XP.
To what extent am I being bottlenecked? Crysis and ARMA 2 run terribly (averaging about 25 FPS with medium settings) but I think this is mainly due to the CPU (and maybe the RAM to some extent).
Yeah, the issue is the processor. The GTX 460 is overkill for your resolution so the strain is going to be on the CPU and a dual core at 2.7ghz ain't that great these days. Have you considered replacing the motherboard if it is really that poor for overclocking? With a decent motherboard and cooler that processor should get up near 4ghz and that should cost you less than $100.
i suggest that he should find the cheapest msi/gigabyte/asus/ p45 around, that should oc better than cheap g41 (i have a feeling that's an ecs, my e5200 on a ecs g31 can barely hit a 100mhz oc as well)