Thinkpads Forum

Hey all!

I need to know what to do if I want to have 16GB of ram on my T420s? What modules do I need at what speeds by what brand? Do I have to use proprietary ram? And finally, do I need a bios update/revision? Thank you for any and all of the help you can give me!

You can have up to 2x8GB=16GB of RAM in there, either DDR3-1333/PC3-10660 or DDR3-1600/PC3-12800 will do.
Get Samsung, Hynix, Elpida, Kingston, Crucial etc. (but NOT any so-called Value-RAM).

Nothing else needed, but make sure the laptop is off and main-battery removed, before you swap them.

Hi, I upgraded my T420s with 16GB RAM, with a kit from Kingston (KVR13S9K2/16). It is in their ValueRam category (but bought it before reading your post). It was properly detected by the laptop and seemed to work fine for a while, but then it started getting random crashes. After some testing with memtest86, I got a lot of failures. I switched back to the old 8GB set I had kept, and no problem. So the Kingston RAM is definitely bad.

I wonder what makes the ValueRAM series from Kingston inferior, knowing that Kingston RAM is otherwise pretty good. Do they use memory chips from inferior manufacturers? Or chips that are not tested as thoroughly?

Anyway, do you think the G.Skill F3-10666CL9D-16GBSQ would work fine? Is G.Skill a good brand?

Thanks!

G.Skill uses memory chips from different manufacturers.
They DO test them properly first, so no objections against G.Skill (I have G.Skill RAM in my Desktop).

The ValueRam is only minimally tested, they are 2nd choice leftovers.

G Skill is okay. I have bought and used a lot of G Skill and never had a problem.

Geil and PNY are the only name-brand company I have had repeated bad experiences with. PNY seems to be gaining popularity again so maybe they stepped their game up.

Posted from my 420 with 2x 8GB!

I have Kingston HyperX Impact Black 16 Gt KIT (2 x 8 Gt) 1866 MHz DDR3L-SODIMM CL11 on my T420. This together with modified bios and SSD is a nice combination. However, I don't know if there is similar bios for the s-model that can use the memory with full speed.

Pricing for DDR3 ram has dropped to the point where there is really no reason to settle for off-brand parts.
If you search for "Crucial 16GB (2 x 8G) 204-Pin DDR3 SO-DIMM DDR3L 1600 (PC3L 12800) Laptop Memory"
on ebay you'll see a listing from Newegg which is pretty reasonable, at least compared to what it used to cost.

I've been testing a pair of these in various machines (T420, T420s) for about a week and they seem
to be pretty solid.

I've also used Kingston and Patriot in the past, and have never had any problems with them,
but I have had some off-brand parts fail.

Hi again,

I received and tested the G.Skill F3-10666CL9D-16GBSQ and it seems fine. No error with memtest. The RAM sticks have Hynix chips on them.

(For the record, I had tried DDR3L RAM before and it wasn't even recognized at POST, so I don't know if DDR3L is fully supported on the T420s, or if it was just bad luck...)

I'm not having a problem with mine, but the T420s BIOS is so buggy that
it would not surprise me. Booting from USB seems to be a real challenge with
these machines.

Tx20 and Tx30 non s and s cannot use DDR3L. Use DDR3 with 2Rx8 (16 chips per module) and brand names/major makers in order to have successful 16GB operation. I'm really tired of people here not aware these notebooks have not went on to newer DDR3L yet till T4x0 series.

Cheers, thinkpadcollection

Not according to this thread:

http://www.tomshardware.com/answers/id- ... -slot.html

but there are apparently a lot of substandard DDR3 sticks out there.

More here:

http://superuser.com/questions/564175/1 ... -overclock

Both my T420s and T430 work with aCrucial 8GB DDR3L-1600 module, combined with a 4GB DDR3-1600 1.5v module, no problems so far.

bit_twiddler wrote:Booting from USB seems to be a real challenge with
these machines.

Indeed!

There is a technique described in this thread:

https://forums.lenovo.com/t5/ThinkPad-T ... 397/page/2

but I haven't had time to try it yet.

Crucial seconded. CT8G3S1339M.M16FDD

thinkpadcollection wrote:Tx20 and Tx30 non s and s cannot use DDR3L. Use DDR3 with 2Rx8 (16 chips per module) and brand names/major makers in order to have successful 16GB operation. I'm really tired of people here not aware these notebooks have not went on to newer DDR3L yet till T4x0 series.

It's the memories which are backwards compatible. For example Kingston HyperX HX318LS11IBK2/16 is a kit of two 1G x 64-bit (8GB) is DDR3L-1866 CL11 SDRAM (Synchronous DRAM) 2Rx8, low voltage, memory modules, based on sixteen 512M x 8-bit DDR3 FBGA components per module. Total kit capacity is 16GB. Each module kit has been tested to run at DDR3L-1866 at a low latency timing of 11-11-11 at 1.35V or 1.5V.

So these run with 1.5V if mb cannot provide lower voltage.
EDIT: As above told I have these and running these with help of modified bios at full speed (1866).

Hello,

When I choose RAM for my machines, I try to buy certified modules. I plan to buy Kingston modules for which Kingston certifies the compatibility with the T420s. The reference is KCP313SD8/8 (you can use two of those to have 16 Gb in your Thinkpad).
You'll find plenty of infos on Kingston's site if you search memory modules : http://www.kingston.com/us/memory/search/options

Have a good day !

W.

EDIT : On this type of machine, I prefer to use 1.5V memory modules with 1333 Mhz frequency. It seems that some modules at 1.35V with a frequency of 1600 MHz are compatible. I have a friend who uses some G.Skill F3-1600C11D-8GSL ( http://www.gskill.com/en/product/f3-1600c11d-8gsl ). Everything works fine, according to him.