What are the ranges of frequencies of RAM supported by TravelMate P259-G2-MG?

GajalShankar said:

Now everything is solved thanks a lot for sticking with me for this long conversation 

No problem at all, I like to help and talk haha

Besides, you should now have a clearer understanding on how things work regarding RAM and the maximum of systems (without overclocking).

GajalShankar said:

Besides, you should now have a clearer understanding on how things work regarding RAM and the maximum of systems (without overclocking).

Yup
Now, I'm getting both 2666Mhz and 2400Mhz RAM cheaper than 2133Mhz RAM. 
as they all are going to downclocked to 2133Mhz 
Shall I go for 2666Mhz or 2400Mhz getting both at the same price under 40 dollars at Amazon?

You will be adding it as a secondary stick to what you have right now right? Remember that matching RAM for it to be working in dual channel may be challenging (as noted in my guide).

For that reason I'd go with the 2400 MHz one, because it is closer to what you already have. Remember that it has to have a 2133 MHz profile and ideally one that matches the timings of what you already have for it to work. It is quite normal to have such a profile to be honest, it is nothing fancy but since it's Amazon, if it were not to work you could always return it and buy a different one.

Checking if it's working in dual channel is easy after it is installed, the Memory tab in CPU-Z will tell you already. When you have it, please post the Thaiphoon information for the 2 modules you'll have installed, I'm curious to see how similar they are.

GajalShankar said:

Understood but what if I installed RAM let's say having more CAS Latency it might not be able to work with my profile as it doesn't match the timings 
only, in that case, I have to return?

I'm afraid so, it may happen that there are no matching profiles, or sub-timings not often specified don't match the sticks may be incompatible.

That's why I mention that the best way to get things working is getting matched memory (those sold in pairs) or finding the exact same model as the one you already have "second hand" in the guide. The rest is trial and error (more often than not memory controllers accommodate and things work though).

The one you need to look for if you want a second hand one just like the one you have is "ACR24D4S7S8MB-8", check eBay for example and see what prices they're at, in case the one you bought doesn't play nice with its companion that is...

They have to match too... I explained a bit more in detail in the guide because there are all sort of things that can be the source of incompatibilities.

But in your case, knowing the stick you have has profiles for running at CAS 15 and 16, those are the ones you want at 2133 MHz. What makes it hard to buy a single stick to complement another that is going to be downbinned is that profiles at lower speeds aren't specified in their spec sheets.

For example, you mentioned two Crucial sticks, one at 2400 MHz and another at 2666 MHz. I'm quite sure they both can run at 2133 MHz too, really, but no spec of them lists the profiles at those speeds.

That's why I was interested in knowing the full info Thaiphoon is able to reveal about the chips themselves, because they'll be posted and anyone in your situation would also benefit from it.

EDIT: Just in case, the whole guide about RAM upgrading was here: https://community.acer.com/en/discussion/608352/guide-how-to-find-out-if-you-can-upgrade-the-ram-and-which-one-you-need

That's the thing, they never specified the profiles they have burned into the chip's SPD unless for the main speed rating of the RAM. On top of that, CPU-Z doesn't show all of the profiles the card supports. Compare mine for example:

CPU-Z:



Thaiphoon:



CPU-Z showed the ones for 2666 MHz, but not the other ones, noticed how it's shown in CPU-Z as JEDEC #6 (so that's the 6th profile). In the screenshot of CPU-Z you showed before the first one read JEDEC #9, so there were 8 more profiles below that frequency not being shown there.

As with many things in life, specialized software trumps generic ones, hence the trial and error. Get one, and how that any of the profiles your current one has matches any of the ones the new one supports

If there are matching profiles it is done automatically, and memory controllers are quite permissive these days, but there's always the possibility that something makes things not compatible.

When buying faster RAM than what the computer supports yes, it's buy and try, because the timings at other frequencies are not advertised.

When buying RAM at precisely the speed the computer supports, the timings are specified in its spec sheet, so it's easier, but there's always a trial and error factor involved haha.

I doubt they'll tell you anything authoritative to be honest, you have more luck getting a proper answer here than with them. In this matter though, it'd have to be an engineer answering the question so... trial and success (most likely) or trial and error (and then exchange the RAM for another one).