I'm having a laptop which is powered by i5 3230M with 6G memory (1 x 4G and 1 x 2G). Sometimes I can feel the lag while I'm working on multiple IDEs. So, how much more memory do you guys suggest?
(2 x 4G) or (1 x 4G and 1 x 8G)

2x16

2x4 minimum

2x16 to never worry again for a few years to come

@IllSlapU I'd love to do that mate! But there is a scenario called "lack of money" 😆

@IllSlapU True that!

Alternatively, you could get an SSD, speeds up everything including paging.

Always try to have the same memory bar in your banks. Simple as that ^^

Without looking into the data sheet I would assume that your cpu supports dual channel ram. This only works well if the ram bars are identical.

The amount? Just check your current ram load while you are working and experiencing 'lags'. 6gb full? Then you should consider 16gb(2*8) ... Using sth arround 4gb, 8 should be fine (2*4)
From what you describe you should be fine with 8 ;P

Another thing that will definitely boost your system is an SSD if not already installed.

I have 16GB (2x8) and I only face troubles when using Android studio, other than that I can run a VM and visual studio and Firefox with no trouble.
My VM has 8GB ram assigned to it

@gitpush Yeah, that's what I was thinking. I only experience lag when I'm running Android studio and Spring tool suite simultaneously. And I don't run VMs or any other video editing heavy softwares

@Rohr Yeah, I don't run any VMs or use any heavy video editing softwares. I just use my laptop for my Dev activities like running MySQL and IDEs like Android studio, IntelliJ and Spring Tool Suite. So how much RAM would be good for this type of usage?

2x4gb is enough.

2x8gb is not overkill. (And not that much more expensive I think)

And if you don't currently use one - an SSD will make a HUGE difference

@RickDiculous179 The thing is, I don't run any VMs or use any heavy video editing softwares on my laptop. I just run some IDEs like IntelliJ and Android Studio. So how much memory should be a good bet?

@EmptyStack I'd use 16gb.

They will happily eat it up

@RickDiculous179 Yeah, that's what I was thinking about!!

If you can find the same 4gb stick with cheap price, you can go for that. But upgrading from 6gb to 8gb isn't really that big of an upgrade. So if you have any money saved just go for 2x8gb.

Pro tip: Always go for RAM modules of identical size. Like 2x4GB, 4x2GB etc.
Most laptops and computers use 2 or more channels to access data in RAM. When you have only modules of equal size, you'll have the best speed because the whole RAM is in dual channel mode.
If you have like 2GB+4GB modules, only 2x2GB will use dual channel and the additional 2GB are in single channel (half as fast). 😉
I'd recommend either 2x4GB, which will be MUCH faster than your current system, or if you have the monetas, go for 2x 8GB.

@PonySlaystation Monetas is the whole point here mate!! 😆

Our company upgraded all dev laptops to 32 GB and it's barely enough for many devs.

@Trablarer Memory modules are pretty expensive. Couldn't agree more!!

@EmptyStack basically, you can not have to much ram. Sure, I would ask myself to seek a doctor if I put 128gb+ in my workstation, but to give and advise between 8 and 16gb I would recommend 16, if the price is reasonable and you are willing to pay a bit more (if you calculate the price per GB, 16gb is cheaper - if you know what I mean)

If you look back what requirements workstations had in the past (like 512mb ram, how the fuck can I fill them) and see now that some ide's have no problem to fill out 8gb and waaay more you should consider 16gb to be happy for a longer period of time. Since there will be no point in time where programs starting to use less ram and resources :D
So you may not have to buy another upgrade to 16gb in the near future, if 8gb are not enough anymore.