Which 4GB RAM is suitable for 2GB RAM Kingston KVR1333D3N9/2G-SP

First you should always check :

Maximum RAM supported by your Motherboard (further MoBo)
The datasheet of the current ram -> Your ram's datasheet

As you can see your RAM runs on 1333 MHZ with CL9, CL value needs to be the same, on the installed ram and on the new ram, or the modules will not be acceptable by your board together and it will declare memory failure.(this is very important) , some will argue that not always this is the case, but keep in mind, normaly it results in no VIDEO signal (black screen).

If your MoBo supports lower/higher clock speeds(1333mhz) for ram, and if you combine it with lower/higher clock,

The two modules will work effectively at the lower speed.

Your compatible RAM is KVR13N9S8/4 datasheet

Complications of uneven RAM settup.

With equal amounts of memory in both slots, memory can be "interleaved" so that successive chunks of memory alternate slots. That way, memory accesses get distributed to both slots almost perfectly evenly, allowing their bandwidth to combine. With uneven amounts, memory cannot be interleaved and has to be mapped first to one stick and then to the other. A program that is accessing a large contiguous chunk of memory will find almost all of its accesses going to one stick, and there will be no bandwidth combination

This answer on SuperUser -> Source

In one word you loose the meaning of DUAL-CHANNEL, better to buy a KIT of 8GB ( 2x4GB on 1333MHZCL9/CL10) or 8GB KIT of 1600mhzCL11 but then you need to check either you need to O.C. your MoBo or update Firmware -> Your Mobo datasheet here

dExIT

Posted 2016-08-12T09:46:28.427

Reputation: 344

His mobo supports Dual DDR3 1066/1333/1600 meaning, it supports those clock speeds, and if the ram card the OP gets is within that range, it will most likely downclock the ram speed to the closest it supports. Also, CL isn't important as its expected the ram card conforms to one of the JEDEC or SPD specifications. – Frostalf – 2016-08-12T11:58:03.390

Please mark as answered – dExIT – 2016-08-12T11:58:09.147

My system hangs up while working on Vmware and other s/w. So, as per you, which will be a better choice buying same 2gb ram (2*2gb) or buying the 4gb recommended by you to improve performance of my pc. – bob – 2016-08-12T11:59:33.610

(2*2) or (2+4) gb ram? – bob – 2016-08-12T12:00:27.837

@Frostalf can you vouch for what you're saying, and that other people will read this, and make a mistake, will that be a Super User answer ?

Anyways, like i said, people will argue, one's setup and expierience is not GLOBAL for all – dExIT – 2016-08-12T12:01:36.617

@dExIT Since you want me to vouch for my knowledge on CAS Latency. http://superuser.com/questions/988551/does-ram-latency-timing-affect-motherboard-compatibility

– Frostalf – 2016-08-12T12:02:30.453

@bob Compare prices between 22gb and 24gb you will understand :) – dExIT – 2016-08-12T12:02:55.433

@Frostalf See that looks like a legit and based on something. Thus again, had a lot of issues with Macbooks, and older MoBos who do not work in this scenario you mentioned, so again this is not UNIVERSAL. EOD ! – dExIT – 2016-08-12T12:04:30.147

@dexit Price isn't a concern. My point is which will give better performance buying same 2gb ram to make it (2*2gb) or 4gb ram suggested by you to make it(2+4)gb ram. – bob – 2016-08-12T12:06:54.797

@dExIT Apple has its own specifications of ram to be used on their mobos. https://support.apple.com/en-us/HT201165#link6 Bob if you use 2 of the exact same ram, you can utilize Dual Channel which effectively doubles the Memory Bandwidth, IE how much data can flow to and from the ram cards at once also it allows the memory between the two cards to be interleaved instead of programs being mapped to one or the other. However the performance is neglible meaning you most likely won't notice a difference, but its generally recommended to use the same ram cards in each slot.

– Frostalf – 2016-08-12T12:13:42.127

@bob Would be wise in your case to use Dual Channel as it could increase performance in your VM's – Frostalf – 2016-08-12T12:20:08.580

@frostalf Thanks, but dual channel increase perfomance by 5-6%. And using (2+4)gb will give me more ram and as per 'flex mode' 2+2gb of ram will work in dual channel while remaining 2gb of 4gb ram will work in single channel. That's what i am confused about? – bob – 2016-08-12T12:32:19.353

@bob Your estimated figure of performance is off in that it varies on your setup you have and the programs you intend on running or your scenario etc. Have a look at this page http://nucblog.net/2015/09/dual-channel-vs-single-channel-does-it-matter/ This explains quite a bit of dual channel and how it can help

– Frostalf – 2016-08-12T12:58:13.573

@bob We are going into a discussion about, ideas and what if's. The ideal setup is to have a KIT-OF-2 inside, 2+4 is not advised. If you dont want to buy a new KIT which costs under $45 then just install what you have for now, BUT THERE IS NO NEED TO BUY a KINGSTON... you could easly buy any other brand as long its basic settings add up.

Im using IN3T4GNABKR ( Integral KIT 2x4GB ) costs 25 pounds... man 25pounds. Please close the topic, or ask for moderation. this is goind nowhere, thus my answer is wasted at this point, and this discussion is just measuring weeners... – dExIT – 2016-08-12T13:47:00.217

Which 4GB RAM is suitable for 2GB RAM Kingston KVR1333D3N9/2G-SP

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