Memory Module Upgrade Dilema

If you’re concerned about compatibility, the only way to be sure is to use a matched pair binned into the same package. As far as brands go these days I'm moving to TEAMGROUP for RAM do sell DDR2. Crucial also makes good modules, but they are a bit pricey at times. If the laptop uses DDR3, this should work, as 1600MHz modules do downclock to accommodate older laptops.

The rule of thumb I use is if I can get a matched set for not much more than 2 individual modules, it’s not worth the effort I will need to put in to try and bin two unique modules, especially given once the RAM is no longer made I will not be able to readily match it without ripping it all out and trying again anyway in most cases which I had to do to my 2012 Mini due to a single module failure on the RAM I got with the machine having a partial failure. Outside of TEAMGROUP and Crucial/Micron, most of these modules are Chinese factory rebrands. That said if the laptop has a weird true maximum you can't ignore like 4GB due to the chipset, you cannot readily find you may need to use these modules. No reputable vendor still makes 4GB DDR3 modules I know of.

Since we don’t know what laptop you have, we can’t help you find a matching set to replace it. It looks like DDR3 from the photos (and the notch), but some of these older low-end laptops continued to use DDR2 for a bit. When in doubt about being able to mix and match successfully, buy a factory-matched set of RAM. The work needed to make it work generally is a pain for novices unless you find a module with the same P/N.