I've read Lenovo's docking station for the W520 lacks USB 3.0 ports, so what's the whole idea? I was hoping to have all my USB 3.0 stuff connected to the docking station.

Docks not made just for the W520, it works on almost all the current Gen Thinkpads, even the cheaper ones. Putting USB 3 would require a driver update for all the Thinkpads that use the dock, as Sandy bridge has no native USB 3.
Even w520 doesn't come with native USB 3, its a third party add on card made by renensas Electric and requires third party drivers to work.
Lenovo would not build a dock that required separate drivers every time you used it.

Thanks Kaze, pitty I always used docks with my X models but doesn't make any sense without USB 3.0

BTW: I noticed in your signature you have 32Gb
I want to upgrade too and and have been trying to find answers before about the best route.
My W520 model 4276-23U came pre-configured by Lenovo with 16Gb.
I know its 4x4Gb but not sure if they are the speediest ones that the W520 board could support?

I wish to upgrade mine from 16Gb to fastest 32gb.
Would you care to tell me what are my options for 32Gb ?
What kind of 4x8gb exactly would I need ?

I'm currently using Corsair DDR 3 1333.
You can go for the faster DDR 3 1600 but I'm not sure if it's going to be stable at that clock rate.

PLus DDR 3 1600 is very expensive, so my suggestion is just get yourself a set 4x8gb DDR 3 1333.
As for make and model. The cheapest ones are Corsair, and G Skill right now.
I would say go for G Skill over Corsair. I've noticed some memory stuttering issues with my Corsair set.
I regret not getting G Skill now.

As far as performance, if you can afford 32GB of DDR 3 1600, then get it, but as far as cost is concerned, DDR 3 1333 is much more realistic.

Thanks Kaze,

I am looking for the best performing and most reliable SODIMMs 32Gb configuration I can get.
I am taking your advice to choose Gskill over corsair

Can you tell me if these ones are the best ones available ?
And also what's the difference between the two ?

G.SKILL 8GB 204-Pin DDR3 SO-DIMM DDR3 1600 (PC3 12800)
Laptop Memory Model F3-1600C10S-8GSQ
Cas Latency: 10
Timing: 10-10-10
http://www.newegg.com/Product/Product.a ... 6820231581

G.SKILL 8GB 204-Pin DDR3 SO-DIMM DDR3 1600 (PC3 12800)
Laptop Memory Model F3-1600C11S-8GSQ
Cas Latency: 11
Timing: 11-11-11
http://www.newegg.com/Product/Product.a ... 6820231579

I really want the fastest reliable ones that the W520 could utilize, money is not an issue here.

Cas Latency is the difference.
The lower the number the better.
In this case.
The 69 dollar one is better.
I would get 4 sticks of those.
Remember don't mix DDR 1333 with DDR 1600 it will drop the speed to the lower model.
If you want the full 1600 performance, then all four sticks must be 1600.

Good luck with your G Skill Ram.

Hope it works out for ya.

the docking station isn't the limitation.   the W520's NEC/renesas USB 3.0 controller only has two channels and both are used up by the W520 itself.   the dock would need a separate USB 3.0 chipset to meet your request and there's no channel to connect it.

an external USB 3.0 hub might be an option but you'll be limited to a maximum of 500 MB/sec sequential transfers through whichever USB 3.0 port is used on the W520.   for most users this would be a non-issue.

Thanks so latency of 10 is the best there is for 8gb sodimms?

On top of that every Thinkpad that is docked would then require a separate driver to be installed for the USB 3 Card to work, which would create complications.

If the series 3 dock was made just for the W520 it might make sense, but the series 3 dock is compatible with just about every Thinkpad under the sun, so adding an external USB 3 card into the dock would have made no sense considering half the Thinkpads it's made to work on have no USB 3 support to begin with.

From my experience USB 3.0 is all hot air, It doesn't even saturate Sata 2 speeds, so 500MB/s is completely out of the question. USB 3.0 currently has lower transfer speed then eSata.
I tested the W520s USB 3 vs the Esata on an identical 8 Bay RAID Array.
The USB 3 maxed out at 180MB/S transfer speed.
The Esata maxed out at 250MB/S transfer speed.

So all this talk of maximum 500MB transfer is all theoretical mumble jumbo, it's about as useful as a multiverse quantum computer.
USB 3.0 in it's current revision is SLOW.

I think they should have had a USB controller built into the dock. The whole purpose of a dock is one latch and you're on the go. If it's becoming more than that it defeats the purpose. But I was thinking there's that huge dock (do they still make it?) that you could even have a picture card in there, maybe that could hold a USB 3 card, though that dock was huge and I haven't heard about it for awhile.

Well USB 3.0 is certainly a huge improvement over USB 2.0 that's for sure. For example I use a CF card reader and it makes a huge difference on USB 3.0. I remember reading somewhere I think on Tom's hardware they said eSata was same speed as USB 3.0 but it's interesting your findings are different.

But the fact is most affordable low profile external HDs are USB and not eSata which is more reserves for Raid drives

A new dock for W520 is coming and it's gonna include some USB3 ports. Take a look at the change log for the v2.1.32
http://support.lenovo.com/en_US/downloa ... D=DS015025
* (New) ThinkPad Series 3 Docking Station with USB 3.0 family.

Oh... Thanks a lot for the info. Huge thanks. Just yesterday I ordered the old dock out of no other choice, now I should see if it's not too late to cancel