1 stick of ram?

[DeathMetalJedi]

can I use just one stick of ram in my machine?

[[☥] - CJ -]

You can yes, but if its only a 4GB stick you'll want more
If its an 8GB stick that'll be fine

But all in all, Dual Channel is better, but theres no harm in just using one.

[Washell]

Originally posted by ☥ - CJ -:

but theres no harm in just using one.

Aside from (slightly) less performance.

[PardonTheSuit]

Sure thing! I am doing that with my build so that if I want to add in more ram later, I can.

[DeathMetalJedi]

How much slower will one 8 gig stick be than two 4gig sticks in dual channel?

[Washell]

Conclusions
Besides that, theoretically, the dual-channel mode doubles the bandwidth between the CPU and the memory, it does not mandatorily result in a perceptible impact on the performance of a specific program. In most of the games we tested, there was not significant performance gain when we enabled the dual-channel mode.

In some cases, there was actually a performance drop when the dual-channel mode was enabled. It can be a simple statistic fluctuation (the ideal was to repeat each test dozens of times in each configuration to avoid it, which is not viable) or even a behavior of the CPU memory controller, working more optimally (maybe with smaller latencies) in the single channel mode.

The fact is that, in the configuration we used an in the games we select, there was no advantage in using memories on dual-channel. This means that, in some cases, when an 8 GiB module is less expensive than two 4 GiB ones (for example), you can install only one memory module with no fear of losing performance.

But please keep in mind that those results apply only for the hardware and software configuration we used. With a different setup, results may be different.

Read more at http://www.hardwaresecrets.com/does-dual-channel-memory-make-difference-in-gaming-performance/7/#4Y4VCXM9D4VTqyjG.99

TL;DR: barely noticeable when it comes to gaming. Very noticeable when it comes to memory intensive tasks like video editing.

At the end of the day, if you have a motherboard with 4 slots, just spend the extra 5 bucks and get 2x4GB. If you have 2 slots and you really, really, really can't afford to go to 2x8GB now, you could go for the single stick.

[Aliquis Freedom & Ethnopluralism]

Yes you can.

As for saving space for future upgrades it's only really relevant on mini-ITX motherboards (two slots) and laptops (two slots), micro-ATX and ATX you have at-least four slots normally (not with H110 for instance, with B150 you should have) and hence even if don't want to get the higher amount of RAM right now you'd still have two slots available later.