Lenovo X220 (laptop) memory upgrade: CL11 vs. CL9 and manufacturer-specific considerations

[Dipak C]

Hi all,

Long-time reader, first-time poster here. I'd like to upgrade the memory in my Lenovo X220 (64bit i5 core) which currently has 1 stick of 4gb (below are CPU-Z screenshots with detailed specs). I'm confused as to whether I'm restricted only to CL9 (which is what's currently in my laptop as indicated by the CAS Latency stat below) or whether my laptop will support CL11 (which has received far better reviews on Amazon.com).

Also, if I'm only able to use CL9 memory (which would limit my options) should I stay away from memory that's advertised as "for Mac". I ask because this specific stick from Crucial has received a lot of positive reviews on Amazon. (If I'm able to use CL11, I'd most likely buy this stick, also from Crucial.)

Am hoping someone can help me make sense of the situation! (Obv, please let me know if I'm thinking about things incorrectly and if there are other, more important considerations to be mindful of, e.g., power sufficiency, etc.)

Thanks!

Two screenshots from CPU-Z which show detailed specs of the memory that's currently installed:

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[JobCreator]

The CAS latency of memory is all internal. The type of laptop/motherboard will not have bearing on the CAS latency. The only thing that may interfere with it, is if the motherboard does not allow you to manually set your RAM timings.

That memory you have is DDR3-1333MHz. You're looking to upgrade to DDR3-1600MHz. That may also be an issue. Your motherboard may not support 1600MHz. If not, it will simply run at 1333MHz instead.

CAS latency does play a small part in how fast a given stick of RAM is. The lower, the faster it's able to perform one "cycle." However, speed plays a way bigger role in performance. For example, the difference between 1333MHz and 2000MHz is going to give you a much bigger performance increase than CL11 vs CL7.

I would go with the second stick you listed. This one: http://www.amazon.com/gp/product/B005LDLV6S/ref=s9_simh_se_p147_d0_i3?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=search-desktop-advertising-no-results-center-1&pf_rd_r=1G278DQRCMXS7C38VWGQ&pf_rd_t=301&pf_rd_p=1912906122&pf_rd_i=Crucial%20ddr3%20cl9%20204pin%20lenovo

 

[Dipak C]

And, just to confirm, it's okay if the two sticks installed with my laptop have different specs, correct? For example, if my motherboard does support 1600mhz memory, will it be a problem that I'm running two sticks, one at 1333mhz and one at 1600 mhz?

 

[JobCreator]

Imagine two runners. They're best of friends. The faster runner will slow his/her pace to match that of the slower runner so they can chat while jogging. The same applies to RAM. The 1600MHz RAM will lower it's speed to match that of the 1333MHz. It would be best to get an additional stick that has the same timings as the one you have. It's very important to get the same voltage memory. That's one that hasn't been mentioned. Lenovo uses, for the most part, low voltage memory. So, 1.3V Crucial memory SHOULD match that.