DDR3 Upgrade: 8gb 2666Mhz -> 16gb 1600Mhz?

As per title, I currently have this 2x4Gb kit:

• 1 x TeamGroup Xtreem LV "Frost Edition" 8GB (2x4GB) DDR3 PC3-21300C11 2666MHz Dual Channel Kit= £65.99

but thinking of changing to 16GB as 2x8GB rather than 4x4. Looking at this kit:

• 1 x TeamGroup Vulcan RED 16GB (2x8GB) DDR3 PC3-12800C9 1600MHz Dual Channel Kit (TLRED316G1600HC9DC01)= £59.99

I got the 2666MHz kit initially thinking the extra speed would help, but now seeing some games take my RAM usage to 100% I'm thinking the extra capacity would be helpful over the next couple years.

The cheaper alternative would be to run my current kit @ 1600MHz and add in another 2x4Gb kit.

What would you guys do in my position?

I would get the 2x8gb and sell the 2666 stuff on fleabay.

If you want 16gb then buy the two 8gb sticks and sell your current ram, mixing RAM isn't worth the hassle. Your board only supports dual channel so you might as well just get two sticks.

Thanks both, I think I'll look at getting 2x8Gb sticks (probably at Christmas when I get some cash). then sell the current stuff.