choose 'cas 9 > 7' or 'DDR3 1600 > 1866'?

[Milanzer]

I'm building a new system with an ASRock Z68 Extreme4 and Intel Core i7-2600K. I'll probably be housing it in a Cooler Master CM 690 II Advanced case with the stock fans for now. I've built a few systems but I have not previously done overclocking. I'm not looking to push any limits, but I may do a bit of overclocking of the no brainer stuff like bumping the 2600K up a few notches.

Looking at the memory, I'm trying to balance cost and performance. I'm not sure I feel like going with the DDR3 2133, partly due to cost and partly it feels like it's pushing the overclocking limit a bit for me (really don't feel like spending lots of time tuning and debugging although I do understand the process of enabling XMP and getting the BIOS timings is straightforward).

I was thinking about either the CAS 7 DDR3 1600's (F3-12800CL7D-8GBXH) or the CAS 9 DDR3 1866 (F3-14900CL9D-8GBSR). Assuming I were getting them at the same price (newegg has them within spitting distance of each other at the moment) and I was not concerned with trying to overclock beyond the rated timings, which of these two choices would be better performing?

Any other opinions?

Thanks for the time.

cheers,
Kevin

[ilbJanissary]

A simple calculation I have seen used a few times to compare memory at different speeds and timings:

Speed (MHz)/CAS Latency = Performance

So with your two selections,

1600MHz/CAS 7 = 229
1866MHz/CAS 9 = 207

I'm not certain exactly how accurate this comparison is, but it would weigh more towards the 1600 MHz, CAS 7 RAM. Those numbers are close enough, though, that it probably makes very little difference either way. I would lean towards the 1600/7 personally, but AMD seems to work prefer lower timings, and Intel seems to prefer higher speeds. In your situation, thus, the 1866MHz may be preferred.

[Tradesman]

The Snipers give you a lot more range, I've got 16GB on an ASRock Fatal1ty Perf. and can run them from 1600/CL7 to 2000/CL10, currently at 9-9-9-27 CR1 1.52 1896 running a 2500K @4.874, so they definitely, will play well, I'll know more about then come mid week, put this together the evening of the first and going to wait a couple more days for the Artic Silver to cure, those it's been right around 31C now all day. Would like to get it stable about 5.2 then really feel out the RAM