Specs - (Intel i5-7200U CPU + 500 GB Nvme SSD)
and Currently, I have 8GB DDR4 2400 Mhz(Single Channel), and I want to add one single 1x8GB RAM to another slot.
Here are the results from
speccy describes I have one slot available for upgrade also I checked on Acer site (it is expandable up to 32GB)


Unlike desktops, mostly SO-DIMM Based RAM(Non -ECC and Unbuffered/Register) are generally supported in notebooks.
As DDR4 2400Mhz is already supported it seems there won't be a problem to upgrade DDR4 2666MHz while upgrading but to clarify
Will my laptop support 2666Mhz without causing any compatibility heating issues?Here are some listed I searched for
https://www.amazon.in/Kingston-Technology-HyperX-2666MHz-HX426S15IB2/dp/B01N7K4CEU/ref=sr_1_5?dchild=1&keywords=8gb+ram+for+laptop&qid=1595620125&s=computers&sr=1-5https://www.amazon.in/Crucial-CT8G4SFS8266-Unbuffered-SODIMM-Retail/dp/B071KNKBQ1/ref=sr_1_8?dchild=1&keywords=8gb+ram+for+laptop&qid=1595620125&s=computers&sr=1-8
FAQ & Answers
In any case, please suggest me which one to buy as I don't know about the availability of the exact model of RAM I have currently having.
Answering the question you have, no, there's no benefit of installing 2666 MHz RAM if it's going to be clocked at 2400 MHz or less; aside from the monetary benefit if it costs less.
Your TravelMate P259-G2-MG can take a max mem of 32GB it has 2x slots (2 banks of 1) and comes OEM with 8GB removable ram. It can take a range of ram from DDR4-2400 SODIMM and DDR4-2666 SODIMM to DDR4-3200 SODIMM. It also has a storage drive form factor of M.2 SATA 3 - 6Gb/s 3D NAND M.2 Type 2280 Internal SSD. See this Crucial site recommendation of both ram and M.2 ssd for a guidance of what you can put into your TravelMate P259-G2-MG here: https://www.crucial.com/compatible-upgrade-for/acer/travelmate-p259-mg.
Also, if you combine a DDR4-2400 in one slot with a DDR4-2666 in the second slot then your ram will run at DDR4-2400 speed and adding DDR4-2666 will NOT make the ram run at 266MHz as the ram will run to its lowest denominator speed and you will be waiting your money with the more expensive DDR4-2666. Try to match the ram with the same timings and always the ame speed and preferably the same manufacturer, as that is the only way that you will get “Dual Channel” mode for you ram e.g. and the max is a kit of matching timing, speed and manufacturer like 2x 16Gb DDR4-3200 SODIMM kit, that will give you the best result for a total of 32GB. Will my laptop support 2666 MHz without causing any compatibility heating issues? That depends room temps and of how hard you push your TravelMate P259-G2-MG e.g. gaming and what demanding software you have, the most and best way is to cool your laptop with a laptop cooler as to reduce temps.
Your TravelMate P259-G2-MG can take a max mem of 32GB it has 2x slots (2 banks of 1) and comes OEM with 8GB-DDR4-2400 removable ram.
The TravelMate P259-G2-MG can take a range of ram from DDR4-2400 SODIMM and DDR4-2666 SODIMM to DDR4-3200 SODIMM. It also has a storage drive form factor of M.2 SATA 3 - 6Gb/s 3D NAND M.2 Type 2280 Internal SSD. See the “Crucial” site recommendation of both ram and M.2 ssd’s for a guidance of what you can put into your TravelMate P259-G2-MG here: https://www.crucial.com/compatible-upgrade-for/acer/travelmate-p259-mg
Since @GajalShankar gave us the model of the processor his laptop has, we know its memory controller only runs DDR4 memory at 2133 MHz unless overclocked. And memory overclocking is not something you can do out of the box on a laptop, it requires hacking its BIOS at the very least.
As I said in the guide, any module that also has a profile for what your processor expects may run, even if it is rated for higher clock speeds, but it won't be running past the max the processor expects. For example, since you have DDR4-2400 installed @GajalShankar, if you open CPU-Z and go to the memory tab I bet you won't be seeing its DRAM frequency going to 1200 even if you do things that are taxing for the memory, it'll stay at 1066 at max.
Therefore, I'd only get DDR4-2133+ memory if it were cheaper than DDR4-2133.
I got confused and didn't know whom I should give "yes" that answered my question billsey , aphanic or StevenGen ?😅😅
****************-----------------By StevenGen-------------------------****************
I need little clarification as I too read the same on crucial website (this became the foremost reason to ask this question) as StevenGen said:
StevenGen you also said if I keep 1x8GB DDR4 2400MHz in 1st slot(as it is now) and go for 1x 8GB DDR4-3200 SODIMM kit in 2nd slot, then dual-channel will work on based on lower threshold, i.e. 2400Mhz and if I go for 2x16GB 3200MHz then only It can achieve up to 3200Mhz. Cool, I got it.
Let's say I have (1x8GB DDR4 2400Mhz in 1st slot and 1x8GB DDR4 3100MHz in 2nd slot)
Ques) Can I disable slower RAM from the BIOS itself so that whenever I want more performance than more amount of RAM I can simply disable slower one? (using one at a time that way we can achieve 3200Mhz playing with the tradeoffs)
If yes then Since I use hibernation frequently will there be an issue in transferring RAM data from HDD back to the different Speed RAM?😅
****************-----------------By aphanic-------------------------****************
Considering Next possibility, what aphanic said that crucial website is inaccurate, also proved by that intel spec sheet that processor i5-7200U can only support max up to 2133MHz.
https://community.acer.com/en/discussion/608352/guide-how-to-find-out-if-you-can-upgrade-the-ram-and-which-one-you-need
But as you stated earlier that it could support max upto 2133Mhz so this post signifies
Therefore, I'd only get DDR4-2133+ memory if it were cheaper than DDR4-2133.
<b>Understood, but how real-life scenario can be justified like If we try to push hardly my filling the RAM and swap space excessively or video editing then also it will reach to a certain limit like 2400Mhz RAM to some 1400Mhz?<br></b>
<b>Also, you are trying to say it's just a marketing term or it can go beyond only in the cases of desktop.<br></b>
<b>Correct me if I went wrong</b>
I guess you are more experienced, can you answer these lame questions?
1. You mean to say there be misinformation by Crucial(manufacturer) and Intel(foundry) about the specifications?
2.billsey said: As 2133Mhz is the max limit, then the only reason Acer has given 2400MHz RAM is that they were getting 2400 Mhz RAM cheaper than 2133Mhz for the same storage capacity?
3.No matter what the speed of the RAM is, it always works at a comparatively lower clock speed than actual as aphanic said.
Please Help me to decide what's the conclusion is -
Guys, please don't think I'm wasting time by asking unnecessary questions I'm just curious to know.
I hope the next comment will give a fair and reasonable answer keeping all the points discussed.
The memory controller nowadays lay in the processor itself, not in the motherboard, that's why the specifications for the processor (when talking about Intel) are as accurate as they can be, without overclocking (overclocking the memory in laptops is a no-no because it implies hacking its firmware too).
I very much doubt Acer overclocked the memory controller for that particular machine during manufacturing, it is possible, but I find it unlikely. It is wasy to see though, CPU-Z is capable of showing in a semi-real time manner (it polls ever X seconds) at which frequency the RAM is running. So does HWiNFO if that program is more to your liking.
Fire it up, you'll see the DRAM frequency alternating states, based on whether the computer is used or not, it's saving energy by running slower. For example, mine is resting at this moment so it downclocked:
If you do something, even if it is not as intensive as running Prime95 with large FFTs, you'll see that value ramp up, but my assumption is that it won't ever get past 1066.5-ish, which means the RAM is effectively running at 2133 MHz (double that). That would be because of the limit I talked about, because Intel chose 2133 MHz, to be the expected DDR4 frequency for non-soldered RAM for that processor. Mine is 2666 MHz:
There are times, in which because of shortage of components, or others being cheaper, faster graded RAM is put in a computer. For example a friend of mine had his A515-54G shipped with DDR4-3200 RAM. It worked, because the chip had a profile for running at 2133 MHz, but that's it, it won't be getting past that.
What's more, if you were after specialty RAM, performance-oriente RAM, they normally state the timings of the RAM for the speed it is rated at. They won't tell you the timings for 2133 MHz in my chip for example, even when it can and will run in a computer that only expect that, so it gets complicated comparing if you were looking for performance.
Look at the profiles of my RAM for example:
This 16 GB stick would work in your computer without a doubt, even though it is DDR4-2666 and it has 4 profile for running at that frequency (probably to accommodate, or play nice with other, less performant chips), it has 2 profiles for DDR4-2133 (starting from the bottom the two that list frequency being 1067 MHz. Hell it would even run in a machine expecting DDR4-1866!
But do you see those timings? (and those are but a few) They generally advertise the best ones and for the memory speed the RAM is rated at. In this case, they advertised it as DDR4-2666 CL15 (15-17-17-35).
And that's my whole reasoning for which RAM stick(s) to choose, knowing your limits, getting higher than that is something I'd only do if it's cheaper as it won't be going any faster than the limit.
I hope I didn't contribute to the confusion, but shed some light on it :S
considering overclocking has never been applied as it is restricted in notebooks
If the chip your friend had a profile of running at 2133Mhz just as mine. Also, DDR4 3200Mhz RAM worked but was he getting downclocked to 1600MHz/1330.5MHz or only up to 1066.5Mhz?
It would downclock to save power when not needed, but that's done automatically and nothing to worry about; the thing is that it never, ever, got past DDR4-2666. Put in other words, the DRAM Frequency CPU-Z reports never got past 1330 MHz.
But my DDR4-2400Mhz stick is behaving poorly that way as it is never going beyond 1066.5 Mhz
Why Shouldn't it reach till 1200Mhz?
Here are all the screenshots merged in one image
You can put a DDR4-3200 stick in there, it will never get past 1065-ish (2133 MHz when doubled) much less 1600 because of the same reason, hence my recommendation to aim for DDR4-2133 memory primarily, but if there are cheaper RAM that's rated for higher speeds it will possibly be compatible too if it's capable of running at DDR4-2133 and the memory controller will make sure of that. It's the one choosing so to speak.
I may have to revisit the memory guide if that isn't conveyed clearly
EDIT: Let's do something, run Thaiphoon (disregard the warning at its start, that's for overclocking and it's prohibited in the firmware) on it and list the profiles your memory has:
But I'm getting 1066.5Mhz (for 2400Mhz behaving as 2133Mhz) even the processor I have limited profile for running at 2133 MHz at max.
What's the catch here(is it only due to memory controller)?
This is the output using
It is certainly possible to overclock the memory controller to accept and work with RAM at speedier clocks, but it's out of the question (not only it's against ACUA, I wouldn't go there in a laptop).
Running at 2666 MHz max, we both have an i7 10510U and that's what it expects; but yep, that's the thing, for RAM clock speeds it all boils down to what the processor and the memory controller wants.
When you see the frequencies being half it is because the first D of DDR stands for double, which may be confusing but you get the drift.
This line was only the part of ambiguity here
-A515-54g shipped with DDR4-3200Mhz RAM. It worked because chip had a profile for running at 2133Mhz where the processor you said is i7 10510U?
which is not the case he has the same processor as you which can operate at your speed 2666Mhz i.e 1330Mhz