memory type 2133 or 2400

[Steve20181]

When I bought HP Pavillion 15-cc563st (12gb) , the specs said that it uses ddr4 2133 memory. I wanted to upgrade it to 16gb so I bought ddr4 2133 memory. Now that I opened it, I see that it has ddr4 2400 memory sticks. Does this motherboard support 2400 memory speed? Should I get 2400 memory or should I just use what I already bought?

[GBL84]

Hello @Steve20181,

Your PC should support both. But when it comes to speed, that will not make huge difference.

So please use the one which was bought 2133, rather investing more again.

Tested by Crucial : http://www.crucial.com/usa/en/compatible-upgrade-for/HP---Compaq/pavilion-15-cc563st

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GBL84

I am not an HP Employee

[Steve20181]

How much max memory does this model support? Is it 16gb or more?

HP Pavilion 15-cc563st

[mdklassen · Accepted solution]

> Now that I opened it, I see that it has ddr4 2400 memory sticks.

> Does this motherboard support 2400 memory speed?

> Should I get 2400 memory or should I just use what I already bought?

In addition to the memory-chips on each stick of RAM is a tiny SPD ("Serial Presence Detect") chip.

For one of my DDR3 RAM sticks, the SPD states:

         Frequency CAS# Latency RAS# To CAS# RAS# Precharge tRAS tRC Voltage
JEDEC #1 444.4 MHz 6.0  6       6 16 23 1.500 V
JEDEC #2 592.6 MHz 8.0  8       8 22 30 1.500 V
JEDEC #3 666.7 MHz 9.0  9       9 24 34 1.500 V

showing that the RAM can run at slower speeds, in addition to the "best" speed (666.7).

I suspect that your DDR4-2400 RAM has an SPD that specifies the values when "downgrading" itself to DDR4-2133 speed, thus implying that you can "mix" the two different speeds of the two sticks.

Question: will you notice the speed-difference between 2133 and 2400 RAM?

(2000, 2133, 2266, 2400) ==>  (100%, 106.6%, 113.3%, 120%.)