Thinkpads Forum

Hello friends!
I spent some time researching possible CPU upgrades for the T420.
I have a high end i5 nVidia unit and I would like to upgrade the unit to its limits.
I have an AMD Radeon SSD on its way.
I want to go with a quad core CPU IF POSSIBLE.
Researching showed mixed answers so I am posting to get the story straight.
IF i7 Quad Cores are possible (ivy bridge maybe even?), which quad core would be THE FASTEST option? (price is not an obstacle).
As for memory I would like to go with 16 or 32GB
What is the limit there and the maximum supported memory speed by the chip?

Thank you so much!

Hi,
I have already seen some T420 and T430 with QuadCore CPUs, however I don't know which one would be best for you.
But what do you Need this extra power (consumption) heat and cost for?
I never had any Speed Problem with either the 2520M or the 2540M, the only thing I would upgrade if it was possible is from Sandy to Ivy Bridge.
Sadly this does not work easily, only with a modified BIOS.
Officially you can only have 8GB of RAM, but 16GB of RAM is also possible.
DDR3 1866 does work, but to exceed a certain clock Speed you will Need a modded BIOS as well.

Greeetings,

Dark Nûmenor

There's a thread on NBR about upgrading T420 with a QC i7 from a few years ago, so it's doable.

This was SB to SB, not SB to IB which I'm not even sure is possible.

Ivy Bridge CPUs are not possible on T420 because of BIOS support.

OTOH there's the Coreboot firmware for the T420 with Ivy Bridge support:https://www.coreboot.org/Board:lenovo/t420. Windows is listed as "tested", but I have absolutely no idea how well it works.
Also, it require a hardware flashing with an SPI-compatible device like a BusPirate or even a Raspberry Pi.

Correct, Ivy Bridge support is experimental and requires specialized hardware to directly flash the BIOS chip, however it has proven that it is possible and hopefully will lead the way for future, more average-user-friendly mods.

With the i7-2640m (the fastest mobile Sandy Bridge dual core i7), my machine reaches upper-mid 80s C fairly easily; once it exceeds 90 it starts to throttle back pretty severely. Look here for some more details regarding my temperature observations - http://forum.thinkpads.com/viewtopic.ph ... 99#p761531

If you need parallelism more than clock speed (based on the fact that (4) cores running at 2 GHz with (4) parallel worker threads is faster than (2) cores running at 2.8 GHz) and you aren't as concerned with the single threaded performance (max. turbo on the lower end QC models is 2.9 to 3.1 GHz vs. 3.5 GHz on the dual core i7) loss of the QC models that will work best in the T420... then a QC upgrade may be beneficial. It all depends on what you intend to do with the machine. Keep in mind though that any quad core's TDP is 45W and the TDP of the heat sink in the T420 is only 35W - so you're probably going to experience throttling at any heavy loads involving more than two of the cores.

If you want the best of the performance world the x20 series has to offer, look into a T520 or W520, either of which will support the i7-2860QM which has a base clock of 2.5 GHz and a max. turbo of 3.6 - and in the case of the W520, greatly superior GPU options over the NVS 4200m or HD 3000.

Sell it and buy a faster thinkpad! I've upgraded thinkpads over the last 15 years and there's always some other bottleneck. For what you'll spend on CPUs, memory, SSDs etc, you could get the same performance for less by selling the T420 and buying a 1 year old higher spec unit.

sktn77a wrote:Sell it and buy a faster thinkpad! I've upgraded thinkpads over the last 15 years and there's always some other bottleneck. For what you'll spend on CPUs, memory, SSDs etc, you could get the same performance for less by selling the T420 and buying a 1 year old higher spec unit.

I won't speak for the OP, but I will speak for myself - I won't buy anything newer than a *20 series because of the design changes (primarily the keyboard). I might consider a *30 series unit now that there's a functional classic keyboard mod - but unless Lenovo returns to some of their pre-2012 designs, I won't get anything new[er] than what I already have. But this is a whole different can of worms which I need not open further.

Point being, there may be a reason something newer hasn't been done - and newer isn't always the best answer based on the needs.

PS - I have so far spent a net of $500 on my W520 which I got pre-maxed out from the factory and includes my purchase of an SSD, the IPS FHD screen mod, and adding RAM - after selling off the part (screen) I removed. I doubt I could get a W541 for that...

Some news.

i7-2820qm work there prety well. More - http://www.forum.thinkpads.com/viewtopi ... 5&t=121144

16GB SoDimm module (CT204864BF160B) doesn´t work. BIOS see them, CPU-Z to, but system not. I going to try modified BIOS, just for try.

Next step is FHD IPS, then i will have dream machine. Buy 1 or 2 for spare parts and still hoping to Lenovo make something usefull

Python.p wrote:16GB SoDimm module (CT204864BF160B) doesn´t work. BIOS see them, CPU-Z to, but system not. I going to try modified BIOS, just for try.

I don't think that will work. I was of the opinion that 16GB modules are supported from the Broadwell generation onwards...

Tasurinchi wrote:I don't think that will work. I was of the opinion that 16GB modules are supported from the Broadwell generation onwards...

Correct.

I know, but just want to try that...