can you combine 2gb ram with 4gb ram?

The 'experts' say that it's best not to match different kinds of RAM, different sizes of modules. But I've done it twice and it worked okay both those times for me.

I think there are RAM sticks out there that are not compatible with certain other RAM sticks. If this is the problem, you'll find that out. 8^) If I was betting, I'd bet they work fine.

Be aware that the whole memory will run at the speed of the lowest-speed RAM.

The two answers above regard what 4GB (2GB/2GB) mean are essentially correct . If it is a reference to what is installed on a pc it is 2 sticks of RAM 2Gb each. As far as running a game requiring 3Gb of ram ...maybe...maybe not. How much FREE RAM of the 4Gb would be a determining factor in the effectiveness of the game running. Generally the Free Ram figure can be found in an activity panel on a computer.

This thread has gotten a little messy, so I will try to clarify.

You can mix different sizes of RAM, however you shouldn't. You can also match different latencies (speed) but all modules will run at the lowest speed.

DDR requires matched modules in order to work correctly, in the case of DDR1 and DDR2 it requires matched pairs. However DDR3 requires three matched modules in order to run at optimum capacity and speed (Triple Channel interlaced). This is only available with iCore processors, so it will run in Dual Channel mode in any other situation (matched pairs)

Depends on the board. I would expect though that the board is only capable of 2 gigs per slot if the max is 8.

To use different memory modules onto one motherboard...the frequency of the memory shud b same...

It can b of different size, brand.

But only point u need to consider is the frequency of all the modules(stick) u wud b attaching on the MB shud be of same size....(333MHz, 433 MHz, 800MHz)

Yes you can mix different sticks of ram, they should work fine except for optimum performance you should always use matching sticks.

NO!

DDR ram is "Double data rate" -- you should always have 2 matching memory sticks (DIMMS)

For example: 2 x 2GB, 2 x 4GB

Also, if your processor and/or operating system is 32-bits, the max memory you can use is 4GB (3.5GB actually).

yes it SHOULD WORK, though i would still go with the same ones. Because sometimes there are SDRAMS and RDRAM. This can lead to hardware damage. Just make sure they are the same type.

it depends on the board you are using if you have 4gb ram already in one slots of ram then add another 4gb of ram to another slot