I7 920 Memory Overclock question

I don't have an i7, so I can't help you. What I can do though is share this how-to-overclock-the-i7-compilation I posted a while back: Intel Core i7 Overclocking How-to

The memory on your DRAM chips isn't even accessed for the vast majority of memory operations because of the very large caches in the CPU. Because of this, the CPU is pretty insensitive to changes in DRAM speeds.

For example, if 90% of the memory operations are handled by cache, that leaves only 10% which involve DRAM. That means that only 1 in 10 memory accesses is affected by DRAM speeds. If you increase DRAM speed by 10%, you could expect a net performance increase of only around 1%.

There are some workloads which have poorer cache hit rates than average, and they'd benefit more from faster memory. But in general, tweaking memory is not all that productive in terms of improving overall system performance.

Benefit from 'More' memory? Surely. The larger and more complex the objects being worked, the greater benefit from having more resource available. "Faster" memory? As relayed above - any gains would be minimal at best.

You didn't indicate earlier this was for a workstation. Most of the posters here are enthusiasts/hobbyists, rather than having a professional need, so that's generally my mindset when I answer something. Given that, I withdraw my recommendation for overclocking the Processor. Next, I'd like to direct you to the writer of your CAD software, and strongly urge you speak to one of their technical reps regarding the ideal configuration.