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Question

Pairing RAM with one that is soldered on the motherboard

by Aug 3, 2018 6:43AM PDT

Hey guys,

My laptop is the ASUS F556UA-UH71, and its motherboard number is the X556UAK. It has 8GB of RAM soldered on the motherboard itself with the following specs: DDR4 2400MHz, timing: 15-15-15-35. Mind you, even though it's rated at 2400MHz, it runs at 2133MHz due to the processor, which doesn't support frequencies higher than that (i7-7500U). There is an expansion slot and I wanted to expand it to 16GB, not only because of the work that I do and some light gaming, but also to experience the performance benefits of a dual channel setup.

So I did some research to find compatible RAM sticks. If I go with a 2400MHz stick, the best timing that I could find is 16-16-16-39. So my best bet is to go with a 2133MHz, and the best timing on those are 15-15-15-36. Actually, there aren't too many options available for me, the only one that I can choose is the G.SKILL Ripjaws F4-2133C15S-8GRS

My question is, will I run into problems by installing this stick, due the different, but similar timing? Will the difference in frequencies cause problems, even though the 7500U doesn't support higher frequencies than 2133MHz and the one on the motherboard is rated at 2400MHz?

Discussion is locked

5 Posts
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Answer
For this one
by Forum moderator Aug 3, 2018 7:03AM PDT

I'd go to Crucial.com and see what is offered.

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I've already tried
by Jake0991 Aug 3, 2018 7:45AM PDT

This is what I get at Crucial using the advisor tool. I get worse CAS latencies, being at 17, at 2400MHz.

At 2400MHz, there is no stick that can have similar latencies as what I have now. I'd have to go down to 2133MHz to get 15-15-15-36. Which is fine, because the processor doesn't support higher frequencies. What I'm asking myself is, will this cause problems? They are not at the same frequencies.

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Overanalyzing?
by r. proffitt Forum moderator Aug 3, 2018 8:31AM PDT

The RAM at Crucial.com should be what works and is tested. If a person starts analysis they may be lost for some time.

As to installing RAM that is faster than is supported, that's fine. That is, if your car tires can do 120MPH they are fine at 75MPH. Same for RAM. But you would like all 4 tires to be the same make, model but in some cases you can't do that.

This is why I use Crucial.com parts. I don't have to research it much. Just order, install and get back to it.

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Tested?
by Jake0991 Aug 4, 2018 8:22AM PDT

There are thousands of different kind of laptops/desktops in the world, does this mean that Crucial tests each one of their RAM sticks with all computers? lol, It doesn't make sense to me.

Got you, I'll go with the 2133MHz G.SKILL then. Essentially, this concludes that matching the CAS latency numbers is more of an accurate comparison than comparing their frequencies, which will both run at 2133MHz. I was just worried if minor differences in CAS numbers or the different frequencies will cause some trouble. I don't think that I should go for the Crucial stick simply because its latency is slower than that of the G.SKILL.

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I run into folk that won't believe it.
by r. proffitt Forum moderator Aug 4, 2018 8:39AM PDT

I can't help them. Good luck in your search and analysis. Here I'd pop for the Crucial, and get back to it.

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