Oct 10, 2021
So I've been researching how to upgrade the RAM in my PC. I'm new to this but I've been doing research and have asked around cause it's best to measure twice and cut once right.

Processor: i5 7400
Supported Memory: DDR4 2133/2400 mHz (1.35 Volts) [Dual Channel w/4 slots for RAM cards.] | Currently I have a single 8gb stick of RAM.

I know it's best to match up the mHz as well as you can so there is less under performance, the volts (1.35) need to match up and the overall supported memory of course needs to match up. DDR4 2400 mHz being what I've been told to look out for. I know my processor is discontinued so it's been a little harder for me to find out which (usually pair) of RAM sticks I should get and to find all the specks to match up. I'm aiming for upgrading to 16gb minimum, maximum to 32gb considering I'm willing to budget up to $150 to get up to 32gb if capable. Even though my rig does support up to 64gb I think 32gb will be more than enough for the gaming I partake in.

Closing question: Any recommendations on what RAM sticks to pick up?
Thank you
16GB will be heaps unless you like to leave stuff like chrome open in the background with heaps of tabs and if you do do that then that is also extra load on your quad core CPU which is borderline good enough for gaming.
If you are not using over 16GB of RAM having 32GB will make no performance difference.

If you really want 32GB and plan to upgrade the CPU then I would get a cheap 2x16GB 3200c16 kit as then it is good enough to use if you upgrade the CPU\MB before DDR5 becomes the norm but not competly overkill for the current system.
I wouldn't go over 16 GB unless you do heavy multitasking in addition to gaming. You should also buy a complete kit of whatever capacity you want, mixing and matching is never a great idea and can potentially cause problems. Just take out the old stick and put in the new sticks. You can save the old stick for spare, use it in something else or sell it on.

Also something to avoid is excessively high memory speeds. The i5-7400 is officially rated for a max of 2400 MHz DDR4, so you should go with that or 2133. Going over that will result in the IMC being overclocked, and sometimes resulting in other values like bclk being fudged to make the higher speed work when using XMP profiles. This can result in system instability from parts running out of spec. You'd also be paying more for those high clocked kits. Once you get past 2666/2933, the price per GB shoots up rapidly and there's no sense in paying for it when you won't be able to use it.

The 1.35v number you see on the Intel spec page is actually for DDR3L, which is what it runs at. The i5-7400 supports both DDR3 and DDR4, depending on the board design. Most DDR4 is going to run at 1.2v, except ridiculously high clocked sticks that sometimes need extra voltage to be stable at high clock speeds.

And remember that raw clock speeds doesn't necessarily mean better performance. Lower clocked kits with tighter timings can often outperform higher clocked kits with looser timings.
3200c16 kits cost about the same often cheaper than slower kits these days.
Also they typically run ~2133-2400 1.2v on there SPD profile and will only run 3200 1.35v in a MB that supports XMP which with Intel i5 7400 would be Z170 or Z270 chipset.