T420 16gb RAM success stories? Will ECC (or "registered") work?

[TKuser]

I'd like to max out the RAM on my T420 to 16gb. What I'm unclear about is if 10600E (ECC) or 10600R (registered/buffered, probably also ECC) will work, or if I must get non-ECC RAM (as per T420's specs: ).

All the good deals (~$21 per 8gb) are on E and R, apparently pulled from servers. There's suggestion that these won't work in laptops, and I've never seen confirmation that anyone who has 16gb (or at least one 8 stick) in their T420 is using ECC RAM.

(There's also another suggestion that, in servers that are OK with buffered RAM, one shouldn't mix buffered and non-buffered sticks in the same machine. But I'm not even clear that buffered RAM will work at all in the T420.)

Can anyone settle this? Thank you!

[Sweater Fish Deluxe]

Are you looking at SO-DIMMs or regular DIMMs? Laptops take SO-DIMM.

I don't think buffered SO-DIMMs exist and while I'm surprised to find that ECC SO-DIMMs do exist, they're not cheaper than non-ECC SO-DIMMs. I'm not sure whether they'd work, though.

[TKuser]

Ah, I'm sure you're right, Sweater Fish Deluxe. These must not have been SO-DIMM's. The 8gb-in-one-stick PC3-10600 (1333MHz) SO-DIMM's are all a lot pricier.

Can I use PC3-12800 (1600MHz) on the T420? I realize it'll run at 1333MHz, but there are way better deals to be had on PC3-12800's. This post suggested it'll work on the T420.

And if so, could I use PC3-12800 DDR3L? This page makes it sound like it might be compatible with systems that support DDR3, but with lower power consumption.

Finally, assuming PC3-12800 DDR3 and PC3-12800 DDR3L both work on the T420, is there any issue with mixing and matching these and/or PC3-10600?

Thank you!

[TankPad]

Can I use PC3-12800 (1600MHz) on the T420? I realize it'll run at 1333MHz, but there are way better deals to be had on PC3-12800's. This post suggested it'll work on the T420.

Yep, This will work no problem.

And if so, could I use PC3-12800 DDR3L? This page makes it sound like it might be compatible with systems that support DDR3, but with lower power consumption.

The low power ram is capable of running at both voltages, so it's theoretically functional in pretty much all older machines that use non-L. Where it gets sticky is when you want to install non-L memory in newer machines that expect only low voltage ram.

Finally, assuming PC3-12800 DDR3 and PC3-12800 DDR3L both work on the T420, is there any issue with mixing and matching these and/or PC3-10600?

This will work. The faster module will run at the speed matching the slower one. Generally I would always aim to have a matching pair in there though.

[Brad]

Has anyone in this thread actually have ever had 16Gb running in their T420?

Iirc the T420 chipset does not support 8Gb SO-DIMMS in any configuration.

This has been discussed before.

Brad

[Thinkpad4by3]

My t520 recognizes all 16gb in bios. Cant tell past that cuz dont have an os.

Sent from my E6553 using Tapatalk

[Sweater Fish Deluxe]

Everything I've read is that 16GB is supported by all the Thinkpads from this generation from the X220 to the W520, including T420 and T420s. I haven't tested myself, but many people on these forums reporting it works.

Can I use PC3-12800 (1600MHz) on the T420? I realize it'll run at 1333MHz, but there are way better deals to be had on PC3-12800's.

Early T420 BIOS versions apparently allowed faster RAM to operate at faster speeds than 1333MHz, all the way up to 1866MHz. This was removed for some reason though nobody I've seen has reported problems with it. You might be giving up nice features and fixes by using such an early BIOS and I'm not sure you could notice the difference in speeds. I think some of the custom no-whitelist BIOSes had the RAM speed unlocked as well, but I can't tell which ones.

If you're mixing memory sticks of different speed, they'd operate at the lower speed anyway, though.

[TankPad]

Has anyone in this thread actually have ever had 16Gb running in their T420?

Iirc the T420 chipset does not support 8Gb SO-DIMMS in any configuration.

This has been discussed before.

Brad

Yup, I run 16GB ram in my 420 and my X220 without any modifications needed.

[Brad]

I am wrong.

I must have been thinking of the T410 not the T420.

I apologize.

Brad

[TankPad]

I am wrong.

I must have been thinking of the T410 not the T420.

I apologize.

Brad

Not at all. Others may have the same impression so it's helpful.

[TKuser]

Thank you, Sweater Fish Deluxe and TankPad! Really helpful.

Breathing new life into an old XP machine (fully security patched as discussed elsewhere online): I set out to break the 3.5gb barrier by employing the technique of getting an "unmanaged memory"/PAE-capable RAMDisk tool, and then creating windows paging files on the RAMDisk to greatly increase virtual memory without the big sacrifice in speed that would happen if swapping to disk.

I found three such tools: Gavotte Ramdisk (rramdisk) (free), SuperSpeed Ramdisk (abandoned, new licenses not available for sale), and Primo Ramdisk (commercial, 30-day trial).

Gavotte and SuperSpeed both crashed my machine when attempting to use their PAE modes. Primo did not (and also supports hibernation), and so this technique is seeming viable (only tested with 6gb so far). Will buy one or two 8gb RAM sticks and see how it goes.

[Ezhik]

This is the RAM I've been rocking in my T420 for the past year: Crucial 16GB Kit (2 X 8GB) 1600 MT/s (PC3L-12800) 204-Pin SODIMM DDR3L Memory (CT2KIT102464BF160B)

The OS detects it as 1600 MHz, but I have not done any benchmarks.

It works great, though.

[zecho]

I'm working with 16GB/1600 for 4 months without issues.

[thinkpadcollection]

Has anyone in this thread actually have ever had 16Gb running in their T420?

Iirc the T420 chipset does not support 8Gb SO-DIMMS in any configuration.

This has been discussed before.

Brad

Reason is yours failed to work is 8 chips per modules. Sandy bridge and Ivy Bridge processors requires 16 chips per module. And yes I do have T420 and HP ultra slim 8200 (sandy bridge) with 16GB using OEM spec modules from ebay using 16 chips. I did try 8 chips at local store and did not work and had to exchange for Corsair Vengeance PC3-12800 16GB kit (DDR3-1600, 16 chips per module). BTW this notebooks I have is using Micron/Crucial , Elpida, Samsung and Hynix. You can order from Crucial or buy any of these I listed on ebay as well.

Haswell processor is the first to use of 1.35V (aka PC3L or DDR3L). Prior to this was 1.5V except mobile Ivy bridge can use 1.35V but desktop only 1.5V. Make sure the memory is capable of dual voltage. Running single purpose 1.35V at 1.5 is risky and hotter. I have no experience with (also mobile Ivy Bridge 16GB x 2 for 32GB) Haswell and later but they can take high density (8 chips per module for 8GB per module, but to run at 16GB per module will use 16 chips).

Cheers, Thinkpadcollection

[TPFanatic]

PC3L-12800s worked fine in my T520 but did not work in my T500. However normal PC3-12800s worked in my T500.

[avdo]

Micron MT16KTF1G64HZ-1G6E1 PC3-12800 1600MHz Laptop Ram Memory DDR3

x2 8gb Sticks of the above Ram working perfectly at 1600mhz here

This is 1.35v / 1.5v compatible Ram btw