Hi,

I have a very old rig among another and newer one which I don't want to lose nevertheless (FSX, P3Dv4 and some music developping programmes on it...). It contains very old 16gb DDR3 RAM running at 668.5 MHZ !!!!! and I know it is impossible to preserve it into the present 😆 

But I did discover a site which allows to upgrade my old DDR3 RAM by maximum RAM used those days, 4 x 8 GB at 1333 MHz, specified exactly for my motherboard. So my question to all hardware experts here around:

If I replace 16 GB RAM at 668.5 MHz by 32 GB RAM at 1333 MHz, will I have the double speed and performance? If so, I would replace the RAM and the old rig will have a nice life further on....

Thank you for suggestions....

You won't double the performance but you will improve it. You would notice a big increase if you were able to update your GPU that has decent VRAM in conjunction with updated RAM.

Thank you. Regarding the GPU I will have a look at, but RAM will be my main focus.

Are you sure that yours is only at 668MHz? Because as a matter of fact, the DD in DDR stands for "double data" and since decades, the base clock of RAM must be doubled to have the actual clock rates. 

My bet: those 1333MHz RAMs you are looking at run exactly at the same 668MHz as your current RAM (or vice versa, yours is actually also running at 1333MHz). So it would end up in a simple upgrade of the amount. 

But no, I would save the money for something else. Because of what I wrote above but also because four modules might work, but it might also lead to issues, because some mainboards simply do not like all four RAM slots occupied (no matter what they claim). 

38 minutes ago, AnkH said:

Are you sure that yours is only at 668MHz? Because as a matter of fact, the DD in DDR stands for "double data" and since decades, the base clock of RAM must be doubled to have the actual clock rates. 

My bet: those 1333MHz RAMs you are looking at run exactly at the same 668MHz as your current RAM (or vice versa, yours is actually also running at 1333MHz). So it would end up in a simple upgrade of the amount. 

But no, I would save the money for something else. Because of what I wrote above but also because four modules might work, but it might also lead to issues, because some mainboards simply do not like all four RAM slots occupied (no matter what they claim). 

This says it all, so i'd abide by this.

1 hour ago, AnkH said:

Are you sure that yours is only at 668MHz? Because as a matter of fact, the DD in DDR stands for "double data" and since decades, the base clock of RAM must be doubled to have the actual clock rates. 

It is in fact a very old rig, purchased in 2012. So my intention was to get the best possible performance as possible for the mainboard at least - by still technically possibility.

1 hour ago, AnkH said:

But no, I would save the money for something else. Because of what I wrote above but also because four modules might work, but it might also lead to issues, because some mainboards simply do not like all four RAM slots occupied (no matter what they claim). 

Yes, this was my thoughts as well. Regarding this, I did look about for the exact matching RAM/motherboard combination and did found it (it's in German indeed, but this site shows the matching between the RAM and the motherboard...)

https://www.memoryxxl.net/arbeitsspeicher/gigabyte/motherboard-mainboard/ga-z68ma-d2h-b3/

I know about the coercion to buy a new rig every four or five years only to be able run the newest system software, newest flightsim or music/video editing software etc etc.

At current state, I am financially not able and not willing to take part at this ongoing footrace. Regarding this, I am looking for possible alternatives to delay this for a while. Purchasing 80 Euro for this step seems to appertain. As said, I am asking for my second rig, not my main PC.

I hope you can understand my intention.

But I appreciate all your advices so far 🙂

Edited July 7, 2025Jul 7 by Manschy

I totally understand, but as said, the benefit of additional 16GB RAM comes at a risk that having four modules in your mainboard results in issues. So IF you want to go for 32GB, you are better of looking for a 2x16GB DDR3 Kit. Still my advice remains: even those 80€ would be a waste of money. You wont see any benefit and you risk the stability of the system using either 4 RAMs or RAM that is not on the QVL...

And regarding clock speeds, check this out: https://en.wikipedia.org/wiki/DDR3_SDRAM it is as I have written, your current RAM for sure already runs at 1333MHz, those 665MHz are the bus clock speed, which is then doubled (that is why it is called DDR).

Chris, this clarifies a lot, thank you for that, also your explanation regarding the bus clock speed. Learning never stops...