Thinkpads Forum

I ordered an 8GB kit of Gskill Ripjaw memory. The timings are 9-9-9 vs 11-11-11 timings @ 1.35v @ 1600mhz. I currently have 1333mhz Gskill ram in there that is below the 1600mhz supported memory. I also need those sticks for other thinkpads that are 1066mhz bus speed. I read a few reviews on newegg and I am guessing some of the posters had 1066/1333mhz bus laptops and their systems could not run 1600mhz ram.

My question, should the low latency low voltage ram fine on my T420s?

I think you'll be fine, right now my T420s has two memory sticks:

row0: Samsung PC3-10600 - 4GB 1.5v 9-9-9-24@666.7MHZ / PN M471B5273DH0-CH9
row1: Crucial PC3-12800 - 8GB 1.35v 9-9-9-24@666.7MHZ (and 11-11-11-28@800.0MHz) / PN CT102464BF160B.C16

My T420s runs my Gskill ram fine but @ 1333mhz 8-8-8-24 instead of 1600mhz. It's 1600mhz ram but the high end Balistik ram with low latency timings. Is there a way to get into the memory bios on the T420s so I can change the ram settings and timings manually? The bios doesn't seem to have memory tweaking settings.

Hans Gruber wrote:The bios doesn't seem to have memory tweaking settings.

I seem to recall that there was an older BIOS version for most of the *20 series that enabled 1600MHz speeds, but the newer ones trimmed it down to 1333...can't tell you which BIOS you exactly need, some research on your end will be required.

Good luck.

No worries. I prefer the lower latency timings. I have the Ripjaw series Gskill ram not the Balistik, that is Crucial. The sticks don't have heat spreaders like desktop high end ram. Just colorful stickers. The ram is rated at 9-9-9-24 @ 1600mhz and I am running at 1333mhz 8-8-8-24.

On a side note, are there any modded bios for the T420s that remove the whitelist and have 1600mhz timings? I want to put in a Wireless AC card in my T420s.

ajkula66 wrote:can't tell you which BIOS you exactly need

1.37, all the above cripple the RAM to 1333mhz

Hans Gruber wrote:On a side note, are there any modded bios for the T420s that remove the whitelist and have 1600mhz timings?

There is one for the T420 non-s, but take a quick look at this link in wiki, under "Whitelist Removed BIOSes", they mention and addition of an advanced menu for the T420s modded BIOS

I took a look at the links you provided and found that the bios in question may not increase the ram speed to 1600mhz. It removes the white list for wifi cards but there could be better options. I could not download the bios from the think wiki link. See the end of the thread for further explanation.

https://www.bios-mods.com/forum/Thread- ... val?page=5