E6420 RAM Upgrade? Which one?

I'm a fairly technically inclined person, but I haven't kept up with the memory world at all since DDR1 lol... every machine I've ever purchased had plenty of memory in it. However, in this case I ordered a Pre-configured model (for Ships Fast) and I really would like to go from 4Gb to 8Gb of RAM (for virtualization purposes).

Dell's website says:

It came with 2, 2Gb modules:
(According to CPUZ): PC3-10700 (667MHz)

I have the i7 2720QM model, though I would expect in this case that the memory limitations are a function of the motherboard and not the processor?

Anyhow, so I go to Newegg (they're having a sale on notebook RAM) and I see that there are quite a few choices (I seem to recall that when I bought my Desktop RAM so long ago, there was a specific type I could use and the only thing was that better latencies were the goal).

• DDR3 1066 (PC3 8500) (6)
• DDR3 1333 (PC3 10600) (6)
• DDR3 1333 (PC3 10666) (5)

If I'm not mistaken, I would want DDR3 1333, PC3 10666... is this the case? And if so, any recommendations? Because none of the brands under that category really strike me as something I'd want to upgrade with... I suppose I could just get the faster memory and only use it at the speeds the motherboard wants, but the price jump was rather steep...

 

Memory speeds make almost no difference (+/- 1%) in real world usage. Just buy the cheapest one.

 

More RAM > Faster RAM. You will only notice faster RAM in synthetic benchmarks and rendering. Just get the cheapest kit from a brand name with a lifetime warranty. Crucial and GSkill tend to be cheaper than other brands.

 

Yes, but More Faster Ram > More Ram > Faster Ram I think my concern is - which speed would be most appropriate? I'm aware that things like CAS latency don't make a ton of difference, but I would imagine higher clock speed might make some real world improvement.

They're all around the same price honestly, with the exception of the insanely fast memory (DDR3 1600).

Of the companies listed, I'm thinking something like this:
Newegg.com - G.SKILL 8GB (2 x 4GB) 204-Pin DDR3 SO-DIMM DDR3 1333 (PC3 10666) Laptop Memory Model F3-10666CL9D-8GBSQ

 

After C2D, they moved the memory controller into the CPU, so memory speed limitations are now also dictated by the processor in use.

According to the Intel database, 2720QM supports DDR3 at 1066MHz, 1333MHz, and 1600MHz.

Would recommend DDR3-1333 (PC3-10666) or higher. I would suggest Kingston, Crucial or Mushkin based on their reputation for quality and on personal experience. Patriot and G.Skill are up and coming but haven't been around long enough for the track record to say yay or nay. Corsair is iffy.

Sometimes having higher speed RAM on systems which aren't capable of those speeds might still provide better slightly better performance in the form of improved latencies.

Make sure that the speeds provided are stock voltages (1.5V ~ 1.65V). Some DDR3 RAM isn't at the right voltage (older) or requires voltage increases to work at the higher speeds.

 

Good thoughts... I couldn't really justify doubling the cost of the memory for the higher speeds, so I went with:

Newegg.com - Mushkin Enhanced 8GB (2 x 4GB) 204-Pin DDR3 SO-DIMM DDR3 1333 (PC3 10666) Dual Channel Kit Laptop Memory Model 996647

From what you said (and what I found from a quick search), given the choice, Mushkin is a better option Both were free shipping and 10% off with the current coupon.