Corsair's XMS4000 is already at the absolute boundary when it comes to available memory speed with their XMS4000 - no one offers a PC4250 part yet - so in terms of overclocking I was not expecting any huge gains. Nonetheless, at CAS 3 (8-4-4) and 2.8V I was able to push the Corsair up to 262MHz, or a whopping 524MHz DDR. That is the fastest memory speed we have yet seen at OcPrices. One thing that should be noted at this point is that the XMS4000 does NOT like being run asynchronously. If you have plans for running it at 300MHz 5:4 for example, it won't play ball. I thought this might be an issue with just the Asus board, so I switched the Abit IC7 for reference, and it performed even worse - this stuff is strictly for 1:1 users only at this time!
Note that you will almost invariably hit a much higher overclock with 2 x 256MB sticks than 2 x 512MB sticks. Several sites have been hitting 550MHz+ with the 512MB dual kits of XMS4000, but as established in the Ramguy presentation article, the majority of power users are favouring 1GB over 512MB with newly purchased memory.
