So, who knows about RAM speeds?

Higher Mhz speed, means that the RAM is faster but to know if your mobo supports that speed or not you have to check on its website or manual.

Tell us the mobo model.

After 8 GB of ram you will not be able to find any difference... so i think better if you buy a 4GB stick 665..

Which of the 13 songs lololol

if you can notice the difference between something lasting 1ms and 2ms, then maybe, but just maybe, you will notice the difference between 665Mhz and 1333Mhz RAM. But tbh, buy RAM that's identical to the one you're currently using, sometimes different RAM modules can cause silly problems.

RAM speed is only noticable in specific syntetic RAM benchmarks. In normal use, including games, the difference is ~1% (effectively none).

Couldn't find anything about HP 3388 laptop motherboard. Can you say what laptop model that is?

As for RAM speed, I think that buying one 1333MHz stick would work well. It will use the lower speed, but you'll get some benefit from having 8GB and if the chipset supports dual channel RAM (which I imagine it does) you'll also get double the bandwidth.

No it wouldn't you already have 1333. DDR double data rate 665 * 2 ≈ 1333

I don't think you should mix RAM with different speeds since it will run only at the slower clock, but someone else might know better

There's no such thing as DDR3 665Mhz. You're misreading something somewhere. DDR3 comes in 1066, 1333 and for the new Ivybridge - 1600Mhz.

I highly recommend you seek advice from someone you know that knows computers rather than polling a forum of people that don't appear to know anything about computer hardware, you'll just end up losing out or wasting time.

Oh, and better check what RAM speeds your CPU(!) supports. Nowadays, mobos ain't the restricting factor anymore.

And like the others said already, its not that much about the speed, even the latencies are not that important for a "casual" gamer. Just make sure you buy two identical RAM sticks instead of using 2 different ones or at least make sure, both Ram sticks have the same stats (clock speed, latencies, voltage). And yes, you already have 1333mhz, like SOGOR said.

The question is, would it even be worth it? I haven't seen any specs of the SL edition, so you may just post it. If you have that i5 M2410, it only supports 1066 or 1333 mhz RAM, so you wouldn't have to think about higher clocked RAM.

DDR3 1333 MHz is supported from what i read. So if you already have 1 stick then match the one & you will be good. ~665MHz = 1333MHz, one is real clock the other is effective clock. You also need to find out what CL on your current memory is(i am guessing 9 or 8, but you need to make sure).
Download CPU-Z & with that program you get more info & from there it will be easy.

More ram is always better if your system can handle it. From what I read your system should be able to see and use that extra 4 gigs of ram.

With my desktop system, I used 4 gigs of ram with 64bit windows 7 ultimate and then I used 8 gigs of ram and I noticed a difference. Programs opened a little faster, other programs ran through things faster.

The more ram you have, the less caching to hard drive the system has to do which speeds things up.

If your system can handle 1333 ram, then yes go for it. In general the extra speed will help things that run more in ram.

As long as you have a 64bit OS the full 8 gigs will be able to be used.

Bah. I thought this was going to be a discussion comparing ewes-per-hour data...

RAM speeds are at the point of overclocked Processors. Any difference is due to some new technology and not speeds. Though if you find something like 3333MHz...

You probably used Speccy or similar software to check the RAM, it for some reason divides the speed into two (possibly because you have 2 channels / slots or whatnot), so you already have 1333 MHz RAM. And no, difference isn't very significant.

fastest and most is an 8gb stick of 1600mhz ram for a modern laptop(most likely for gaming ones)?

DDR3 = Double Data Rate 3, meaning it pulses on the rising and falling edges of a clock cycle. Speccy only checks individual clock cycles, so it only reports half the speed.

RAMS are cheap now so go ahead for da speed!

example: CL5 = 5-5-5-18-23-3

(CL5 = CL-TRCD-TRP-TRAS-TRC-TRRD)

CL: 5

TRCD: 5

TRP: 5

TRAS: 18

TRC: 23

TRRD: 3

Voltage 1.8V

This is just an example of how the timings are to be set manually.

No, you won't really notice, so just grab 1 stick, but preferably the same model, or at least manufacturer, for compatibility...